Academia

 Academia' (アカデミア Akademia) is a Duel school in the Yu-Gi-Oh! ARC-V'' anime that trains "Duel Soldiers" and is located in the Fusion Dimension. It is run by Leo Akaba under the guise of "The Professor", a man originally from the Original Dimension, and serves as his base of operations.''' The goal of Leo Akaba and as such the goal of the Academia, is to use the power of Fusion to make all the worlds become one. In order to accomplish this, Academia employs its army of Duel Soldiers in order to conquer the other Dimensions by turning its inhabitants into cards. This goal is referred as "ARC Area Project". However, it's revealed that Leo has his own hidden agenda that he never reveals to his students. His real goal is to enact his personal plan, Revival Zero, which is to revive his daughter, Ray.

Strategies
In Episode 40, Serena mentioned that Barrett is using a "By-The-Books" strategy, a kind of strategy used by the Academia.

Recruitment
Once children graduated from elementary school, they are sent to Academia to learn and become Duel soldiers for the completion of the ARC Area Project. Once sent to Academia, nobody was allowed to leave until graduation. Those who escaped will be pursued by the Juvenile Officers to be taken back and punished accordingly or turned into cards. After Yūshō's arrival, those who escaped Academia are taking shelter at Yūshō's underground Duel school.

Reiji's Arrival in Fusion Dimension
Three years prior to the ARC-V storyline, Reiji Akaba had unknowingly traveled to Academia via an inter dimensional transporter while looking for his missing father. He eventually met Serena, who he helped escape from faculty members who were pursuing her, only to have them both caught by Leo and several members of Obelisk Force, the elite vanguard squad. Reiji was confused by the ensuing discussion about alternate dimensions and the Academia, until the squad hauled Serena off and placed a device on Reiji's wrist, which sent him back to Standard, but not before Leo gave Reiji a hint about his goal to unite all four dimensions.

Dennis' Espionage Mission on Xyz Dimension
A year before the invasion, Dennis was sent to Heartland to find one of the targets. There, he posed as a resident and often gathered large crowds of people while entertaining as a street performer. During his stay at Heartland, he witnessed Yūshō's Entertainment Dueling and became entranced by it, sparking his desire to become Entertainment Duelist, which led him to study under Yūshō's tutelage. On one of his street performances, he spotted his target in the crowd; Ruri Kurosaki. Knowing she was one of Academia's targets, he used his "Entermage Trapeze Magician" to draw her away from the crowd and challenged her to a Duel. After finding Ruri, he informed Academia to green-light the invasion. Before setting off for the Xyz Dimension, Leo assigned Edo as the Commander-in-Chief for the invasion.

The Invasion on Xyz Dimension
At some point, Leo ordered his elite vanguard squad to advance into the Xyz Dimension and attack, as part of his plan to eventually unite the Four Dimensions. Without warning, they did so, causing chaos with powerful monsters like "Antique Gear Chaos Giant" and sealing nearly all of the inhabitants of Heartland City in cards in the process. Yūto, Shun, Ruri, Kaito, Allen, Sayaka,  and a few others were the only survivors of the attack. After the invasion commenced, Dennis learned the location of the Resistance's base and called in Yūri. Once Dennis pointed out who Ruri was he retreated, allowing Yūri to Duel and capture her. They were also able to wipe out most of the Resistance  and without any Duels, the soldiers would seal innocent people into cards. The Amazoness Tag Duelists, the Tyler Sisters, Gloria and Grace, were infamous among the Resistance for almost destroying the Spade Branch's Resistance force. Shortly after the first wave attack, Edo encountered a former teacher of Heartland Duel School's Clover Branch, Yūshō Sakaki, after hearing about him spreading his philosophy to bring smiles with Duel. The two Dueled, Yūshō's right leg got crippled during the Duel from Edo's attack. Despite this, the Duel resulted with Edo's defeat. Before anything further could happen, Yūshō got transported to Fusion Dimension, leaving the bewildered Edo to hold a grudge against him and since then was looking for the Entertainment Duelist's whereabout for a rematch.

During one battle, Barrett directed his soldiers to move forward, only to find himself the victim of a Set "All-Purpose Landmine Glaymore" that exploded on him. The fate of his comrades is unknown but Barrett was the only known survivor of the event, being left scarred.

Roget's Betrayal
At some point, Jean-Michel Roget was sent to the Synchro Dimension as an undercover agent to ensure Academia's conquest. He introduced the Real Solid Vision technology to City, which became a crucial tool for the Executive Council to strengthen Security's power and maintain the Tops' dominance in the riots created after Chojiro Tokumatsu's arrest. Once he climbed to the position of the Director of Security, Roget eventually decided to betray Academia, and without informing Leo Akaba he began to make plans to turn City into his own kingdom.

After the invasion, Yūri went to the Synchro Dimension on Leo's order to kidnap Rin. He succeeded just as Yūgo arrived on the scene and escaped using a card. He was then seen at Heartland, secretly watching the confrontation between Yūgo and Yūto from behind a building.

Creation of You Show Duel School
When the first army returned from Heartland, some of the students who participated in the war started to escape from Academia out of guilt of what they have done. They started to doubt the school's plan to invade other dimensions and turn people into cards, even civilians. To prevent this, the Juvenile Officers are dispatched to capture them. One day, when a female student and Asuka Tenjōin escaped from Academia, the officers caught them and sealed the girl in a card. They attempted to seal Asuka away, but Yūshō arrived and defeated them. After hearing the whole story from Yūshō, Asuka decided to defect from Academia and help Yūshō in creating an underground Duel school, You Show Duel School, to shelter Academia students who escaped. Asuka soon became infamous for being the only student that the officers failed to defeat.

Pre-Maiami Championship
During his Duel with Shingo, Yūto asked about the connection between Leo Duel School and Academia. However, Yūto soon discovered that most of LDS knew nothing of Academia and the existence of other dimensions, concluding they are not enemies.

Maiami Championship: Round 1
After Shun Dueled Sora, it is implied that the latter was affiliated with the Academia, as Reiji mentioned they could learn more about it from Sora. During his Duel against Yūya, Yūto revealed that the Academia attacked the citizens of Heartland and sealed them in cards. During this time Sora was transported back to the Academia due to a program on his Duel Disk that activated after revealing his goal of acquiring a powerful Fusion Monster. When Sora came back, Leo had his men check Sora's memories as to find out why Sora had been returned since Standard were not their enemies. From Sora's memories, Leo found out about Yuzu whom he called the "Fourth Piece" he needed for his plan and ordered Yūri to bring her to him.

Maiami Championship: Round 2
While Sora was recovering in the nursery he protested to go back to Standard since there were Xyz Remnants there, Serena eavesdropped on his demands and planned to go to Standard as to prove her strength to Leo in order to be at the frontlines. Several guards attempted to stop her but failed, but Barrett decided to go with her instead of stopping her since it was his duty to protect her. The two arrive at Standard and Serena watches Hokuto perform an Xyz Summon on screen, believing him to be part of the Xyz Remnants, she manages to find him and easily defeats and transforms him into a card. Serena then turns his attention into Yū Sakuragi a prominent Xyz User, in the Maiami Championship. Unfortunately for her, Reiji found about her appearance and correctly deduced she would attack Yū, so he used him as bait to lure the duo.

Barrett vs. Reiji
Serena and Barrett encountered Yū, but before they could attack him, Reiji appeared and ordered Yū to leave, while having Nakajima seal the area so the Academia duo could not escape. Serena attempted to Duel Reiji but Barrett offered to Duel instead, since it was his duty to protect her. Serena stood aside and watched. Barrett and Reiji Dueled, with Reiji noticing that Barrett was a war veteran, as Barrett used burn tactics to rapidly damage Reiji. Barrett praised Reiji for using his own Life Points to maintain the cost of his "Covenant" cards, mentioning that he deserved a war medal for that. Reiji defeated Barrett using a combination of "DDD Marksman King Tell" and "DDD Oracle King d'Arc". Serena attempted to leave, but Reiji stopped her and the two reminisced on their past encounter years ago. A barely conscious Barrett activated his Duel Disk to return to the Fusion Dimension and to give away Serena's location. Reiji offered Serena the chance to join him into defeating Leo, but Serena refused, saying that all she wanted was to earn Leo's recognition. She left, but not before Reiji declared her an enemy should she interfere with him.

Battle Royal
After receiving the transmission, Leo had a meeting with Sora, who requested to be sent back to the Standard Dimension. Leo agreed to Sora's request, but ordered him to look for Serena and make it his priority to bring her back. Sora noted Serena's resemblance to Yuzu and asked why the two looked alike. Leo replied that he did not need to know that and had the Obelisk Force accompany Sora. The Obelisk Force entered the Standard Dimension during the Maiami Championship's Battle Royal, prompting Reiji to cut any transmission that featured the Academia. Sora encountered Shun, Yūya and Knight of Duels students. Sora had the Obelisk Force deal with the Knights while he Duels Shun on nearby ruins. The Knights of Duels were then swiftly defeated and sealed into cards. Seeing this, Yūya became infuriated and challenged the three soldiers to a Duel. Meanwhile, Reiji sent his Youth Force of Lancers, led by Yū.

The Obelisk Force vs. Yūya
While Yūya Dueled against the Obelisk Force "Dark Rebellion Xyz Dragon" to attack them. The trio of soldiers began to panic but they were unable to defeat Yūya, who used "Synthesis Magician" and "Antithesis Magician" to Pendulum Summon "Odd-Eyes Pendulum Dragon" and then used the Pendulum Effects of both his Pendulum Monsters to grant "Dark Rebellion" a Level equal to the Level of "Odd-Eyes". Yūya overlaid his two monsters to Xyz Summon "Odd-Eyes Rebellion Dragon the Supreme King Black Dragon" and used its effect to destroy their monsters, inflict effect damage and attack a number of times equal to the monsters destroyed. This defeated all three soldiers in one fell swoop.

The Obelisk Force vs. the Youth Lancers and Yūgo
More Obelisk Force soldiers entered the Volcano Area and spotted Serena with Dennis Macfield and Yuzu. They escaped, leaving Yū and the rest of the Youth Lancers to fend off the invaders. However the Youth force was quickly overwhelmed and turned into cards. Before Yū was defeated, Yūgo interfered in the Duel after recognizing the Academia soldiers as people he met before. He defeated the soldiers by using their "Antique Armageddon Gear" against them with a combination of his "Clear Wing Synchro Dragon" and "Synchro Cracker" to destroy all monsters with lower ATK than "Clear Wing". Yū realized that he could not fight any further and ran away in a panic without thanking Yūgo, annoying him. Nakajima expressed his concern to Reiji that the Youth Force were unable to repel the invaders and Reiji acknowledged the LDS did not have the strength to fight the Academia, but that his plan for the Lancers was for them to master Pendulum Summon as a new power that could give them an edge in battle. He referred to the potential Duelists as the "Yūya Sakaki Generation".

Academia's goal
While the battles were taking place, Yuzu and Serena talked, and Serena revealed that the Academia, under orders of "The Professor", plotted to make the Four Dimensions become a single world, calling it an "honorable goal". However, Yuzu revealed the truth of the Academia's cruel assaults into other dimensions to Serena and requested for her to seek the truth by meeting Shun, the Xyz remnant she was looking for, to which Serena agreed. Knowing that the Obelisk Force were hunting Serena down, Yuzu suggested they swap clothes so that Serena could meet Shun and confirm the truth.

Yūri vs. Yuzu
Dennis, now revealed to be an agent working for the Academia, eavesdropped on their conversation and met Yūri, telling him of the girls' plan so that he could track Yuzu. During this time, Halil and Olga appeared, mistaking Yūri as an opponent for the Battle Royale, and challenged him to a Duel. Yūri was annoyed, but he accepted their challenge. He easily defeated both of them and sealed them into cards. The Obelisk Force surrounded Yuzu, believing her to be Serena, but Yūri interfered and ordered the soldiers to retreat or he would seal them into cards as well.

He threw the cards containing Halil and Olga at them, causing the soldiers to leave. Yūri tried to convince Yuzu to surrender, claiming it was pointless to fight and that "the Professor" needed her. Yūri challenged Yuzu to a Duel, which Yuzu was forced to accept. Yūya and Gongenzaka, who were looking for Yuzu, encountered Dennis and told him of the attacking soldiers, unaware of his true colors. Dennis maintained his facade by agreeing to accompany Yūya and Gongenzaka. Meanwhile, Yuzu was forced to run for her life after knowing that she was no match for Yūri, who was in hot pursuit with "Starve Venom Fusion Dragon". Before Yūri could find her, Yuzu's bracelet activated teleporting Yūri away, due to Yūgo's arrival. Yūgo mistook her for Rin. Before Yūya could find her, the bracelet shone once more and teleported the two away leaving Yūya, Gongenzaka and Dennis unable to find her. Dennis incorrectly believed that Yūri had finished his mission.

The Obelisk Force vs. Lancers Candidates
Serena, who managed to avoid the Obelisk Force, witnessed Shun being defeated by Sora and thrown downstairs, leaving him injured. Serena activated "Lunar Eclipse" so that the two of them could escape. Sora initially mistook Serena for Yuzu and ordered her to stand aside. Upon recognizing her Duel Disk as being of Academia origin, Sora pursued the pair. The three eventually reached the Volcano Area with Sora requesting to get his "prey". However the two Fuma Ninja students, Tsukikage and Hikage appeared and blocked Sora's path. Hikage decided to face Sora, allowing Serena, Shun and Tsukikage to escape. Dennis, observing from afar, encountered remnants of the Obelisk Force. He told them that Serena was in disguise. The three soldiers asked Dennis if he wasn't coming, but Dennis said he couldn't because there were "too many cameras". The Obelisk Force soldiers then attacked Serena, Shun and Tsukikage, and forcing them into a Battle Royale. Shun wanted to go first, but Tsukikage interfered and fended off the attacks of the three soldiers using "Barrier Ninjitsu of Gathering Shadows". Serena decided to go next and Fusion Summoned "Moonlight Cat Dancer". Before it could attack, the Obelisk Force used "Fusion Dispersal" to counter her monster and damage her, as they prepared for her. Michio Mokota and Teppei Tairyōbata then joined the Duel, but suffered a 2000 LP penalty. Using a combination of "The Legendary Fisherman III" and "Monster Pie" the two were able to damage the entire Obelisk Force for 2000 LP each one. The Obelisk Force used a combination of "Antique Gear Reborn", "Antique Gear Spark Shot", "Antique Gear Booster" to deal enough damage to defeat Michio and Teppei, who were weakened by the penalty. Both were sealed into cards afterward. Before Tsukikage could suffer from the same fate, Shingo appeared and used "Flame Guard" to protect him, having heard the situation from Reiji, but took the 2000 LP penalty. Yūya and Gongenzaka could only watched as Sora sealed Hikage into a card. Gongenzaka then saw Serena, who he mistook as Yuzu, in a Duel and left to help her. Yūya was left alone and challenged Sora to a Duel in order to return his smile. Sora agreed, since he did not like having a losing record against Yūya.

Gongenzaka arrived as Shingo used "Abyss Actor - Devil Heel" and "Abyss Actor - Funky Comedian" to Pendulum Summon "Abyss Actor - Big Star" and used its effect to search and equip it with "Abyss Script - Fantasy Magic in order to return the Obelisk Force's "Antique Gear Triple Bite Hound Dog" to the Extra Deck and break their combo. However, the Obelisk Force used "Antique Gear Rebirth Fusion" to Fusion Summon "Antique Gear Ultimate Hound Dog" and used its effect to halve the Life Points of all their opponents. Gongenzaka took his turn, and used a combination of Pendulum Summon and the effects of two of his "Superheavy Samurai Thief" and a copy of "Superheavy Samurai Courier" in order to provide Shun with the Pendulum Cards that Shingo activated previously. Shingo questioned his move because he thought he could break the combination by himself, but Gongenzaka said it was fine this way. Shun asked why Gongenzaka went so far to give him Pendulum Cards. Gongenzaka replied that Shun was the one who would finish the Duel. During his turn, Shun remembered all the people who protected him during this time, and found the notion ridiculous. Shun used "Devil Heel" and "Funky Comedian" to Pendulum Summon three copies of "Raid Raptors - Wild Vulture" and used them to Xyz Summon "Raid Raptors - Revolution Falcon". Shun used its effect to let it attack all the Obelisk Force's monsters. Its other effect allowed Shun to reduce their ATK and DEF 0 during battle. "Revolution Falcon" attacked and defeated the remaining Obelisk Force soldiers, winning the Duel for Shun and his allies.

Sora vs. Yūya
Meanwhile, Sora and Yūya perform their own Duel with the two trading blows. Yūya was convinced that Sora had become warped and revealed his intentions to bring him back to his "usual self", but Sora refuted this by saying that the Sora that Yūya knew was never his true self; his true self was a soldier of Academia. Yūya disagreed because he remembered that Sora had fun during their first Duel. Sora retorted that he was not being serious back then, but Yūya claimed his smile was genuine and that the two became friends after that Duel. Sora told Yūya that there were things more important than their friendship. Yūya denied this by pointing out that Sora taught Yuzu how to Fusion Summon as a sign of friendship, but Sora claimed he did so merely because Fusion Summon was an honorable mechanic and a power that could make the worlds become one. Yūya argued that fusing the four worlds was wrong, but Sora angrily stated the opposite. Yūya asked Sora if he was aware of the cruelty inflicted into the Xyz Dimension by the Academia, and Sora indifferently stated that it couldn't be helped to achieve the Academia's goals. An infuriated Yūya told Sora that they didn't have the authority to fuse the worlds. Yūya Xyz Summoned "Dark Rebellion Xyz Dragon" and used its effect on Sora's "Death-Toy Scissors Tiger", but Sora used "Death-Toy March" in order to negate the effect and Fusion Summoned "Death-Toy Sabre Tiger", which subsequently revived the previously destroyed "Death-Toy Scissors Bear". The effects of both "Tiger" and "Sabre Tiger" boosted the ATK of Sora's monsters to colossal levels. Yūya then used "Synthesis Magician" and "Antithesis Magician" to Pendulum Summon "Odd-Eyes Pendulum Dragon". He used the effects of both Pendulum Monsters to make "Dark Rebellion" have the Level of "Odd-Eyes" and overlaid both of his Dragons to Xyz Summon "Odd-Eyes Rebellion Dragon the Supreme King Black Dragon" Yūya used its effect to destroy both "Tiger" and "Bear" since their Levels were lower than 7. Sora used "Fusion Front Base" to avoid the effect damage. At this point, Sora regained the same excited demeanor he had during his first Duel with Yūya because Yūya was able to Summon an Xyz Pendulum Monster, while finally realizing that battling Yūya is fun. Yūya agreed to his statement that Duels were meant to have fun. Yūya used the effect of "Supreme King Black Dragon" to attack as many times as monsters were destroyed by its effect. Sora activated "Flame Chain" to lower its ATK, but Yūya countered with "Flame Power" to boost its ATK. The two raced for an Action Card, but were unable to catch it since the Battle Royale timer expired, disabling the "Wonder Quartet" Field Magic and ending the Duel without a result. Gongenzaka and the others, who witnessed the Duel, caught up to Yūya. Yūya mistook Serena for Yuzu until Serena revealed she was not Yuzu. Sora, knowing the mission had failed, activated his Duel Disk to be transported back to the Academia.

Shun vs. Dennis
After the Battle Royale incident, Serena defected from Academia after hearing the truth of their crimes from Shun. The officially established Lancers, made to counter Academia, started their own plans to increase their effectiveness by traveling to the Synchro Dimension in order to recruit allies, though they never knew that Dennis was an Academia spy. Upon arriving at the dimension, Dennis and Gongenzaka were separated from the others. They were scouted by Gallager for his underground Dueling and both met up with Shun, who was part of the underground Dueling circuit. Dennis Dueled Shun, and his Dueling prowess made Shun suspect his identity. Dennis, Shun, and Gongenzaka were arrested, but escaped and was forced to participate in the Friendship Cup.

Friendship Cup
During the course of the Friendship Cup, Reiji heard information from Tsukikage that Security's director, Jean-Michel Roget had apparently came from another dimension and that he brought with himself advanced technology and quickly raised the ranks of Security, while using Gallager in order to recruit strong duelists for himself. This information, along with the use of a Fusion Monster by Duel Chaser 227, made Reiji suspect Roget was actually an agent of Academia. During the last Duel of the first round of the Friendship Cup, Shun was set to battle Dennis, and the latter secretly vowed to destroy the former slowly. Shun had suspicions that Dennis was a member of Academia and he focused on unmasking Dennis. The two started an aggressive Duel, and through the use of "Raid Raptors - Target Flag", Shun forced Dennis to reveal his hand, showing a "Fusion" card. Dennis then used "Antique Gear Chaos Fusion" in order to Fusion Summon "Antique Gear Chaos Giant", confirming his Academia roots and declaring the start of a hunting game. "Chaos Giant" rendered Shun's combination useless, but he was able to survive the attack of "Chaos Giant" with "Raid Raptors - Last Strix". Regardless, the attack on "Revolution Falcon" laid waste to the arena, debris being thrown everywhere. Enraged after learning about Ruri's kidnapping from Dennis, Shun counterattacked by using "Rank-Up-Magic Soul Shave Force" to Summon "Raid Raptors - Satellite Cannon Falcon". This monster reduced the ATK of "Chaos Giant" to 500. Dennis attempted to survive using Action Cards, but the debris from the attack of his own "Chaos Giant" tripped up his D-Wheel and he was unable to and was thus defeated by "Satellite Cannon Falcon". After the Duel, Dennis admitted that Shun had won before passing out. Still filled with rage, Shun tried to seal Dennis in a card but was unable to do so, so instead he attempted to punch Dennis but was stopped by the tournament's staff, who then carried Dennis off on a stretcher.

Friendship Cup Finals
Dennis was being taken to the recovery room when the Executive Council and Security both attempted to take him into custody. Sora saved him and took him away to an alleyway. He explained to Dennis that he was attempting to capture Serena as per the orders of the Professor, and sent Dennis back to Academia to recover from his injuries. After hearing Dennis' report that Yuzu and Serena were in the Synchro Dimension's City, Leo gave Barrett a new mission to go to the Synchro Dimension with the Obelisk Force and capture Yuzu and Serena. He also informed him that Yūri would also come to the Synchro Dimension.

Obelisk Force's Arrival at City
Near the end of the Duel between Crow and Yūya, Sora noticed the Obelisk Force arrived riding on several gliders with searchlights. Sora contemplated on ignoring them, but then remembered how strong Yūya's conviction to protect not only Yuzu, but also Serena, so he decided to warn Crow about it, knowing that Yūya's involvement in the war is unavoidable. The Security and Reiji also noticed this, and Roget ordered Sergey to defeat the Obelisk Force instead, putting aside his plan to retake control of Reiji and the Executive Council.

Obelisk Force vs. Sergey & Reira
Once landed, the Force split up into groups of three, searching for Yuzu and Serena. Those who were to find either of them would alert the others with a red flare. Serena, still incapacitated from Security's attempt to take her and with Tsukikage and Reira Akaba, was found rather quickly and a flare was lit, slowly drawing the Obelisk Force to her location. Several members then entered duels with Reira, with all of them ending up defeated by the young boy. Others approached the Executive Council's building, which was under siege by Security as well. However, Sergey Volkov intercepted them, defeating several members, much like Reira did.

Obelisk Force vs. Tsukikage & Sora
Around the same time, another trio found Tsukikage who was on his way to the underground facility to warn the other Lancers and chased after him. Knowing if he ignored them they will find Yuzu's hiding place, Tsukikage stopped and challenged the Obelisk Force. They held the upperhand until Sora joined the duel on Tsukikage's side, much to their surprise. This trio was then defeated after Sora, with help from Tsukikage, took control of their "Hound Dogs" and turned them against their masters. All of the defeated Obelisk Force members were recalled to Academia near-instantly.

Academia vs. Yūya, Yūgo, and Sergey
Yūya arrived to assist Reira, defeating three Obelisk Force. Barrett then arrived with another group of Obelisk Force and Dueled Yūya. Barrett's Beastborg combo prevented Yūya from attacking, activating spell cards, and summoning monsters, cornering the latter as Barrett interrogate him for Yuzu's location, something that Yūya refused to tell. Sora arrived and took out the Obelisk Force who came with Barrett, but was followed Yūri with another group of Obelisk Force. Before Yūri could Duel with Sora, Yūgo arrived and Yūri decided to Duel him instead, immobilising Sora. The Duel was interrupted by Yuzu's arrival who transported Yūri and Yūgo, and then Sergey who swiftly defeated Barrett, but Barrett successfully brought back Serena with him using the last of his power. With Barrett defeated and Yūri disappeared, the remaining Obelisk Force decided to retreat.

Heartland City
Academia students are still in the Xyz Dimension and continue to hunt down people. Three students manage to corner a man and proceeded to seal him into a card. They also find a family in hiding with Yūya, Gongenzaka, and Shingo. The six of the them prepared to Duel, but the students doesn't recognize the Duel Disks and learn that Yūya, Gongenzaka, and Shingo are Lancers and their mission to stop the Interdimensional War. The students tell them its their mission to finish the ARC Area Project. Yūya tells the hardships he went through and defeats them in a combined Pendulum Summoning with Gongenzaka and Shingo. After defeating them Shingo tries to seal them into cards as payback but is stopped by Yūya. The three students escape only to into Kaito Tenjō, who sealed them into cards.

Juvenile Officers vs. Asuka Tenjōin
Yuzu, who got transported to Fusion Dimension, witnessed a group of people being sent to Academia at the dock. It's revealed that as Serena had said before, Academia are gathering Duelists throughout the dimension to be trained as Duel soldier to complete the ARC Area Project. Once Duelists are sent to Academia, they are not allowed to leave and those who attempted to do so will be recaptured and punished. Yuzu, who got mistaken as a runaway, was chased by Juvenile Officers, but was fortunately saved by Asuka Tenjōin, who took her to You Show Duel School, an independent Duel School created by Yūshō that sheltering Duelists who have escaped from Academia.

Edo Phoenix vs. Yūya
An Academia member, Mamoru Noro, was restless over Edo's absence, the Commander-in-Chief of Academia for the invasion of Xyz Dimension, and protested how they were late to complete the ARC Area Project in Xyz Dimension, worrying the Professor will got mad if they keep prolonging it. Meanwhile, Edo was looking for Yūshō Sakaki whom he had a grudge against. However, he instead encountered Yūshō's son, Yūya, who was also in the middle of looking his father. Once knowing Yūya's connection with Yūshō, Edo brutally attacked Yūya with intention of making him a bait to lure out Yūshō. Edo at first got the advantage, until Yūto possessed Yūya's body to take over the Duel and countered attack, forcing Edo to end the Duel with a draw.

Three more students were sealed into cards by Kaito after being defeated in a Duel.

Yūri vs. You Show Students
Yūri, who returned to Fusion Dimension, encountered a few of You Show Duel School students while they were escorting another Academia Duelist who escaped. He managed to turn one of them into card. Two of the students escorted the escapee to their hideout while the remaining five stayed to avenge their friend who was carded. Despite the advantage in numbers, Yūri easily defeated all of them in his second turn using the combination of his spell card and his ace monster, turning all five of them into cards. He once again encountered Yuzu with Asuka after hearing the attack, but before he could challenge them, Yūgo arrived, which activated Yuzu's Bracelet and transported him away.

Tyler Sisters vs. Allen & Sayaka
After receiving report that Lancers have arrived in Heartland City, Leo dispatched the Tyler Sisters, Gloria and Grace, to eliminate them. At Heartland, the sisters encountered a Resistance Duelist, Sayaka Sasayama, and mistook her for Lancers. Allen Kōzuki then arrived and together with Sayaka, accepted their challenge for Tag Duel. The Sisters' combo that prevent them from destroying their monsters and inflict piercing damage easily overpowered Allen and Sayaka, leading to the Resistance Duelists' defeat. Before the sisters could card them, Shingo and Gongenzaka arrived, revealing themselves as Lancers. Unsatisfied with the previous Duel, the sisters challenged the two of them to another Tag Duel.

Tyler Sisters vs. Yūya & Shun
Tyler Sisters were confronted by Yūya and Shun who arrived shortly after they defeated Shingo and Gongenzaka. Recognizing the sisters as the ones who wiped out most of Resistance Duelists' Spade Branch, Shun and Yūto were more than eager to accept their challenge for a Tag Duel. The sisters quickly turned the Duel in their favour by using the combination of their Spell cards and Fusion monsters that negating any damage from Yūya and Shun and also increasing their LP every time Yūya and Shun summoned special summoned monsters. Shun's continuous Xyz summoning kept increasing the sisters' LP until Yūya came up a counterattack that will wiped out the sisters' LP in one attack. Starting his turn with his Entertainment Dueling, Yūya purposely increased the sisters' Fusion monsters' ATK by using his spell cards before using their own monsters' effects to increase their ATKs above the Fusion monsters'. As Yūya attacked, the sisters were so entranced by the beauty of Yūya's spell cards that they didn't even care when Yūya activated the second effect of his Spell card that reduced their LP to 0, defeating them. Defeated, the sisters were still in shock of how amazing Yūya's Entertainment Dueling was, not minding Noro who ordered them to chase after the Lancers. However, Obelisk Force then arrived and told them that they received order from the Professor to handle the Lancers.

Obelisk Force vs. Yūya, Shun, & Kaito
The Obelisk Force intercepted the escaping Lancers and Resistance who were on their way back to hideout. Since the others were still injured, Yūya and Shun were the only ones who accepted the challenge. The Obelisk Force attempted to defeat Yūya before his turn could even start, but Yūya successfully avoided OTK by using an Action Card to forcefully ended the battle phase. He then countered attack the Obelisk Force who attacked him before, but purposely spared him with enough LP so he they could Duel a little longer, which the Obelisk Force commented as naivety, though Yūya retorted, stating he wouldn't fight dirty. Yūya and Shun's teamwork managed to outwit the Obelisk Force until one of them summoned "Antique Gear Chaos Giant" that triggered Sayaka's fear and caused a debris to collapse right above her. Shun collapsed after he protected her and the Obelisk Force once again ganged up on Yūya and would've defeated Yūya if it were not for Kaito's interference who easily defeated all three of them in one turn. Kaito thought for a moment to turn them into card, but decided not to.

Edo vs. Yūya & Academia Squad vs. Kaito
Shortly afterwards, Edo arrived with his squad, surrounding the Lancers and Resistance who were tending Shun. The Tyler Sisters objected Edo's interference because they have received direct order from the Professor himself, but Edo ignored their objection and told them to stay out of it. Edo then forcefully dragged Yūya to Duel him and trapped them in his magic field, preventing anyone from interfering. While Yūya was forced to Duel Edo, Kaito faced the entire squad alone and easily defeated them all. With the squad defeated and transported back to Academia, Kaito and the rest returned to their hideout to tend Shun's injuries, leaving Yūya to continue his Duel against Edo. Edo able to overpower Yūya by using the combination of his ace monster, "Destiny HERO - Dystopiaguy's" effect and his continuous magic card "Demise Urban". He also used the chain that connected their Duel Disks to prevent Yūya from getting any Action Card until Yūya made use of it to do his acrobatic move, forcing Edo to destroy his magic field. As the Duel went on, however, Edo's rage towards Yūya slowly disappeared as he got carried into Yūya's pace while the latter performing his Entertainment Duel. Yūya used his new Fusion monster, "Brave-Eyes Pendulum Dragon" and an Action Card "Miracle Fire" to defeat Edo, which led Edo to accept Entertainment Dueling. Right after the Duel was over, both Edo and Yūya were surrounded by Academia soldiers that Edo's Vice-Commander, Mamoru Noro, has summoned in case Edo was defeated. In a twist of event, Edo defended Yūya, now convinced that Yūya's philosophy was right and declared he defected from Academia, ready to be branded as traitor if it means he could choose his own path, shocking Yūya, Yūto, and the Academia Duelists. The Tyler Sisters, who were touched by Yūya's Entertainment Dueling since their Duel, also followed the suit. The defection of three high-ranked Duelists caused doubts within the Academia soldiers who surrounded them. Kaito and Allen then arrived with their Resistance comrades, forcing Noro, whose plan has failed, to defect as well, which followed by every remaining Academia soldiers. They were then taken to the Resistance hideout where they started helping the refugees while Yūya and the others were discussing their next step. Edo revealed that there's a way to change back all the people who were carded, and to do so they must go to Academia in Fusion Dimension since all of the carded people were sent there.

Dennis vs. Yūshō
At You Show Duel School in Fusion Dimension, Asuka and Yūgo proposed to Yūshō that they should attack Academia now since six of their students have already been carded by Yūri. The other students also agreed to their suggestion, so Yūshō relented under condition that he will go as well despite his injury. They were interrupted by Dennis and his Academia squad who have found their hideout through several eye witnesses. Dennis greeted Yūshō, whom he referred as "Teacher", revealing their connection as student and teacher during their times at Xyz Dimension prior the invasion. Confident he has surpassed Yūshō as Entertainment Duelist, Dennis challenged his former teacher to Duel him, which Yūshō accepted. Yūshō started his turn by simply set one card and ended his turn, infuriating Dennis who accused him of looking down on him, but Yūshō denied this. Dennis started by summoning his ace monster, "Entermage Trapeze Magician" to attack Yūshō. However, Yūshō activated his set up card to confuse Dennis and the Academia soldiers, giving himself and his students opportunity to escape unbeknownst to Dennis. Realizing he was tricked, Dennis ordered the soldiers to go to the harbour since their intention was to attack Academia directly. Dennis pursued Yuzu and Yūgo who were then cornered, but to his surprise, Yūya, Kaito, Gongenzaka, and Shingo unexpectedly arrived, reuniting with Yuzu while Yūgo got transported somewhere else because Yūya was within the vicinity. Dennis then told Isao Kachidoki who was inside the car that it's his turn to appear.

Isao vs. Yūya
Isao challenged Yūya into a rematch and the Academia soldiers surrounded Yuzu, Gongenzaka, and Shingo while Dennis went after Yūshō with Kaito following him. Yūya reluctantly accepted Isao's challenge, leading the Academia soldiers who were supposed to capture Yuzu to shift their attention fully to Yūya and Isao's Duel, getting excited watching the Duel. Yūya was successful in defeating Isao, making him accepted his Entertainment Dueling. Yuzu quickly led Yūya and the others to the harbor where Yūshō was.

Dennis vs. Kaito
Dennis reached Yūshō just as the ship sailed and challenged him once more. However, Kaito accepted the challenge in Yūshō's stead, revealing what happened in Xyz Dimension. Dennis accepted the challenge, urging the people on the ship to watch the Entertainment Duel. As the Duel start, Dennis quickly was able to gain advantage in Duel due his Xyz and Fusion monsters combo and also his knowledge of Kaito's deck and Duel style since as a wanted Duelist, Kaito's data was stored in Academia's Duel archive. However, Kaito was able to turn the table by summoning "Little Fairy", Sayaka's monster that was not in his data and performed a Rank-Up Xyz Summon, summoning "Neo Galaxy-Eyes Cipher Dragon" that defeated Dennis. Despite Yūshō's effort to persuade Dennis to join them, Dennis refused out of shame after betraying the Lancers and chose to card himself, but not before revealing where Ruri and Rin's locations.

Captain Solo vs. Yūya & Sora
Yūya and the others who were looking for a ship to go to Academia was approached by Serena who took them to a pirate ship that they will use to go to Academia. On their way to Academia, they were ambushed by Academia soldiers and Serena exposed herself to be working for Academia together with Solo and his crew to trap Yūya and the others. She captured Yuzu, taking her into helicopter to Academia whilst Yūya, Shingo, and Gongenzaka faced against Solo. Shingo and Gongenzaka were tied by Solo's crew, giving Yūya no choice but to Duel alone.

Solo summoned his Fusion Monster "Captain Lock" and activated its effect that prevented Yūya from summoning any monster to his field, and Yūya has difficulty getting an Action Card because Solo attacked him and his crew kept moving the ships to steer him away whenever he was about to reach one. He was saved by the remaining Lancers who came to their aide, this time with Crow and Sora joining the group. With Sora's Fusion monster, they were able to defeat Solo and his crew. To ensure that Solo and his crew won't follow them, Tsukikage sabotaged their ship, making the ship to sail indefinitely.

Diana vs. Kaito & Apollo vs. Yūgo
Kaito, Yūshō and Asuka arrived at Academia only to be suspicious to figure out if it was a trap that they walk into since no Academia soldiers on sight. Despite knowing the possibility that it was trap, Kaito still needed to save Ruri who was held in the Western Tower. Yūgo was hiding behind a wall hearing Kaito, Yūshō and Asuka only to be pin by Kaito. Kaito then told Yūgo to hurry as Asuka informed that Rin was held at the Eastern Tower and Yūgo rushed there right away on his D-Wheel. Kaito and Yūgo fought against the guardians of the towers, Diana and Apollo, respectively. Meanwhile, the Professor and his subordinate, Doctor, were watching from the throne room. When he saw Yūshō finally arrived at Academia, the Professor mused that it's the time for him to tell everything to Yūshō. After much struggle against Diana and Apollo's Trap and effect combo, Kaito and Yūgo defeated Diana and Apollo and freed the captives, who unbeknownst to them has been brainwashed into following the Professor.

Rin vs. Yūgo
Shortly after they were reunited, Rin suddenly challenged Yūgo to a Duel, pushing him out from the window. From the throne room, Doctor explained that the Parasite Monster he created, "Parasite Fusioner", was not easy to be taken down since it's implanted inside the victim's brain and able to see through the memories of the victims, giving Rin advantage in Duel since Yūgo was her childhood friend and knew his deck well. While the Professor praised Doctor for the result of his research, he also told him not to place the girls in danger because the girl were necessary for the completion of ARC Area Project, but the Doctor defended his decision by answering that because they're precisely important for the project they need to defend themselves. Despite Yūgo's best effort, he couldn't free Rin from the mind control and she was able to defeat Yūgo using her Fusion monster.

Survival Duel
Seeing the Lancers have arrived at Academia, the Professor ordered his subordinate, Sanders, to deal with them as they have planned and gave specific order that among the Lancers, Yūya was the one they absolutely must eliminate. With the order given, Sanders explained his students their mission and warned them that this wasn't a training, but a real battle. While Sanders and the students were watching the Lancers' arrival, another group of students ambushed the Lancers and led them into a trap, though Sora, Reiji, and Reira were able to get away. Sanders took the captured Lancers into a dome where he challenged them into a Survival Duel battle royal where there will be only one winner while the others were turned into cards. Sanders chose his five best students: Ethan, Emma, Jacob, Bernie, and Ted. Without any choice, the Lancers agreed to Duel. As the Duel commenced, Bernie was immediately carded by a mysterious Duelist. The other students thought that one of them has already defeated a Lancer, but this was proven wrong when Ethan saw Yūya and the others picked up Bernie who has been carded. Afraid, Ethan ran away and bumped into Ted. Before Ted could attack, Ethan reminded him that they need to eliminate Lancers first before Dueling among themselves, to which Ted agreed, but the latter scolded the former when Ethan revealed he escaped because it was four against one. Ethan then also revealed that Bernie has been turned into card and became afraid that they will end up the same way if they lost, but Ted merely scoffed at the thought and confidently stated he could take care all of them by himself and made his way to find Lancers. Ted found Tsukikage Dueling against someone and decided to interfere, but the moment he joined the Duel, he was attacked and carded by the Duelist Tsukikage was fighting against, shocking Tsukikage who initially thought they were comrades. Cornered, Tsukikage left a message for his comrades before he was defeated and carded, which later found by Yūya and Gongenzaka. From the message, Yūya deduced there were 11 Duelists participating, which means there was someone else beside them and the Academia students. At the same time, the mysterious Duelist attacked Ethan and turned him into a card. Shortly after, he spotted Shingo who challenged him and Crow heard Shingo's scream not long afterwards. Meanwhile, the remaining Academia students who were watching became confused and worried when the lost signals increased even though there was no sign of a Duel being commenced. They came to realization that if the signals were right, then the numbers of participants doesn't match. After Shingo and Crow reunited, the unknown Duelist watched them until Emma and Jacob arrived. When the four of them started a Duel, he joined them and received the intrusion penalty while they wondered where he was. The unknown Duelist swiftly defeated Emma and Jacob and sealed them into cards, with Sanders outraged that his top elites were wiped out and couldn't surpass that guy. The students wondered what was happening until one mentioned Battle Beast, alerting the rest that he's just a rumor. The unknown Duelist hunted down Crow and Shingo, before Crow eliminated Shingo from the game by damaging his Duel Disk and engaged the unknown Duelist directly in an attempt to end the Duel in a DRAW. The unknown Duelist was able to survive, but the attack and its location drew him out of hiding. The students were shocked that the unknown Duelist was indeed the rumoured Battle Beast that Sanders told everyone that is the strongest Duelist he has trained. Battle Beast pinned Crow down and sealed him into a card as Yūya and Gongenzaka arrived and attempted to stomp on the card, but Shingo managed to snatch it away from him. Battle Beast then proceeded to Duel Yūya and Gongenzaka, while Sanders told his students that Battle Beast is very hostile and will card anyone, causing him to be defective and imprisoned. He also told them that he was planning on molding them into the strongest duelists but there was no result after his chosen five were defeated. He told them if they don't want to be carded like the first five, they should watch the Duel closely. Battle Beast weathered their attacks by protecting his "Gladial Beasts" with "Medallion of Gladial Beast" and used destruction effects in combination with "Pollice Verso" to quickly reduce their LP. Yūya and Gongenzaka managed to barely survive his subsequent attacks, as Battle Beast blocked Yūya's moves to get an Action Card, forcing Gongenzaka to use one. Incensed at Gongenzaka's resistance, Battle Beast wiped him out with the effect of "Pollice Verso" and prepared to seal him into a card, but was interrupted by the arrival of Jack Atlas. Jack's arrival and intrusion managed to turn the table into the Lancers' favour. Getting impatient at Battle Beast, Sanders decided to join Duel, surprising the students. He told Battle Beast to show his strength and viciousness to the enemy, causing Battle Beast to become uncomfortable, something that Yūya noticed. Sanders told him it was a direct order from the Professor to eliminate the Lancers; especially Yūya Sakaki. He tried to use the second effect of "Tamer Editor" to destroy "Red Daemon's Dragon Scarlight", but Jack prevented it with "Red Armor". Instead he attacked Yūya directly and told Battle Beast to prevent him from getting an Action Card, but Battle Beast simply stood there in shock. Yūya dodged the attack with "Evasion", and Sanders yelled at Battle Beast for not following orders, stating the superior officer's orders were absolute on the battlefield. He told the rest of his students to engrave it into their hearts, as absolute obedience was his cardinal rule. Battle Beast activated his trump card, "Gladial Beast Assault Fort", to protect himself and challenged Yūya and Jack to break through it. Sanders told him to bury Yūya and Jack, but yelled at him again for ignoring orders again and threatened to seal him into a card. To his utter shock, Battle Beast used the effect of "Tamer Editor" to destroy itself and then defeated Sanders, surprising everyone. The students watched as their instructor was defeated and discussed how Battle Beast will turn anyone into a card. But they convinced themselves to take this Duel as another teaching lesson since its supposed to teach them how harsh a real battle is. Battle Beast jumped off the fort and held Sanders down to seal him into a card. At this time, Battle Beast's real feeling was revealed by Yūya: Battle Beast didn't really want to fight. Battle Beast seemed to confirm this by saying that he didn't care about Sanders' orders and resented him for dragging him into a war Academia started on a whim. When Yūya tried to prevent him, the students told him not to interfere as they want him to teach his "victory is everything" doctrine by being an example for all of them. Sanders told Battle Beast to seal him because he can teach his students how harsh a real battle can be. Battle Beast was about to but learned about Sanders goal to create the strongest Duel solider in order to carry out the Professor's order to eliminate Yūya. Battle Beast faltered when Sanders told him that he won't survive if he doesn't defeat Yuya, so Battle Beast postponed his plan to card Sanders and shifted back his attention to Yūya and Jack. Battle Beast brought out "Gladial Beast Great Fortress" and placed all his monsters in the graveyard under it and negate the effects of all face-up monsters on the field. When Jack attack directly, Battle Beast activated the effect of "Great Fortress", letting him Special Summon "Andabatae" with its effects negated and its ATK becomes 1000 plus the number of monsters underneath "Great Fortress" times 1000. Also, when a monster is destroyed by battle or card effect when "Great Fortress" is face-up, that monster's owner will take 500 damage for each monster sent to the Graveyard. But, Jack used "Red Armor" in his Graveyard and banishes it to prevent "Tyrant's" destruction by battle. Battle Beast then placed "Andabatae" back under "Great Fortress" due to its effect and was angry that he couldn't take Jack down. When Yūya attack directly, Battle Beast used the effect of "Great Fortress" to Special Summon "Andabatae". However he couldn't destroy Yūya's monster due to the effect of "Entermate Guard Dance". He then Special Summoned "Gladial Beast Gaizares" while Yūya sent "Entermate Shieldrummer" to attack. His third Special Summoned monster "Gladial Beast Laquer" took on "Entermate Odd-Eyes Unicorn" while his final monster "Augustus" blocked "Entermate Gongcat". The students were surprised at how Yūya survived of all Battle Beast's monsters even though he was seemingly only fooling around. When Yūya had "Entermate Pararhino" attack directly, Battle Beast activated the effect of the "Gladial Beast Noxius" in his hand, Special Summoning it in Defense Position. He was laughing that Yūya used up his attacks and couldn't do nothing now until he wondered why his monsters didn't return. He came out of "Great Fortress" and saw his monsters shooting paintballs, and it turned out his monsters were switched with Yūya's when he used the effect of "Guard Dance" in his graveyard. He was then pulled out of "Great Fortress" by the Entermate monsters as he listened to Yūya tell him how fun Dueling can be and that he should Duel his own way. He watched his monsters be destroyed by the effect of "Entermate Pendulum Art and Clean" while muttering Dueling that hurts people end today. The students were starting to be amazed by Yūya's Entertainment after seeing it for the first time. Battle Beast used the effect of "Great Fortress" to inflict damage for each one, defeating himself. He blamed himself for hurting so many people but Yūya told him he can atone for it since his true self has now returned. Finally freed, Battle Beast cried and apologized for everything he has done. Sanders told Yūya that the Professor's next assassin will send him to his doom as his students take him away. A student then helped lead Yūya up to the surface when he was going ahead. From the laboratory, Doctor watched Ruri and Yūya with Serena, having anticipated something like this would happen so he was glad to place a Parasite Monster into a Academia student in advance.

Yūri vs. Asuka
Yūri confronted Reiji, Reira, Yūshō, Sora, and Asuka in a hallway and threatened to seal them into cards, only to be pushed away by Asuka, while Sora activated the fence to trap him in. However, after pushing Reira out of the way, Sora got trapped between the fence, which disabled his Duel Disk. Asuka told Yūshō to continue on to the Professor while she held Yūri off. Yūri showed Asuka his "Honor Student Deck" and replaced his "Predator Plant" Deck with it. Asuka started swiftly by Ritual Summoning "Cyber Angel Nasateiya" while Yūri requested some time to study his cards as he had no idea how they worked. Despite this, Yūri managed to Summon "Antique Gear Reactor Dragon" and overwhelmed Asuka with it. Asuka used the effect of "Nasateiya" in her Graveyard to Special Summon it from there and take control of "Reactor Dragon" by banishing the second "Nasateiya". She then used the effect of "Nasateiya" to gain LP equal to half of the ATK of "Reactor Dragon" and tried to attack him, but Yūri used "Unfinished Antique Gear" to Special Summon "Antique Gear Golem" and protect himself. She attacked "Gear Golem" twice and used "Fusion Destruction" to banish the three "Fusions" in Yūri's Deck to inflict damage for each one. She tried to convince Yūri that they could be friends now that he felt the same pain while the Professor watched. Yūri then revealed his past how he didn't have any friend due to his skill and the Professor was the only one who acknowledged him, so he has been fighting his best to please the Professor. However, Yūri then revealed that he didn't care about the Professor anymore because sealing everyone into cards made him happy and he will continue to do so until there's no one left, which will prove he is the strongest. Yūri revealed that he had modified the Honor Student Deck by including "Super Fusion" that was immune to Asuka's trap card, allowing to Yūri Fusion Summoned "Antique Gear Ultimate Golem", defeating Asuka. Yūri thanked Asuka for making him realized his new dream: to turn every people in all four dimensions into cards and then sealed her into a card, causing the Professor to stand up in horror. He then lowered the bars that separated him and Sora, explaining that he could have done so at any time, but kept Sora locked up to amuse himself and challenged him to a Duel. Meanwhile, the student told Yūya that Yuzu should be in the laboratory up ahead. Yuya went there as he was told, unaware that the student was also under the Doctor's control.undefined

Yūya & Yūto vs. Ruri & Serena
At some point the Doctor placed a Parasite Monster into Yuzu, brainwashing her. When Ruri ran off to search for Kaito, she ran into Yūya and they both were about to go help Shun, but Doctor activated "Parasite Fusioner" again. Ruri suddenly challenged Yūya to a Duel and declared she will turn him into card, returning to her brainwashed state. Upon seeing Yūya set three cards without summoning a monster, she recognized that strategy as Yūto's. She was surprised when Yūya revealed he was Yūto after hearing the same words she told Yūto. She Special Summoned "Lyrical Luscinia - Assembly Nightingale", which gained 100 ATK for each Overlay Unit. When Shun arrived during Yūya and Ruri's Duel, the Doctor saw him as disturbance and ordered Serena to go deal with him. Ruri revealed "Parasite Discharge", a monster that wasn't supposed to be in her deck, shocking Yūto. She then used the effect of "Parasite Fusioner" to Fusion Summon "Lyrical Luscinia - Independent Nightingale" and inflict damage to Yūya for each level it has. She then attacked him directly but Yūya activated two "Phantom Knights Lost Vambrace" to prevent Phantom Knights he control from being destroyed and lower "Independent Nightingale's" ATK. When Shun was about to go to look for Doctor, Serena tased Shun upon arriving and joined the Duel, promising if Yūya wins she and Ruri will listen to him. Serena Fusion Summoned "Parasite Queen", equipped with both "Parasite Fusioners". When Yūya activated the effect of "Phantom Knights Cursed Javelin" to negate "Parasite Queen's" effect and reduced its ATK to 0, Serena's "Queen" was unaffected by card effects due to the effect of "Parasite Plant" and destroyed "Cursed Javelin" while setting a card. When Yūya tried to make her remember of Lancers, she revealed she does remember but it's all in the past and showed the insects created by the Doctor. She also revealed that the insects were in their heads, including Yuzu's, enraging Yūya who then switched placed with Yūto, shocking the two of them. Seeing Yūya suddenly changed into Yūto, the Professor stood up in surprise, realizing there's already second personality inside Yūya. When Yūya and Yūto said they were going to defeat Doctor and save the girls, the Doctor dared them to do it if they defeat Ruri and Serena while laughing with Rin and a brainwashed Yuzu behind him.undefined

Yūri vs. Sora
Yūri Dueled Sora and pushed him into a corner until Sora counterattacked with "Death-Toy Mad Chimera". However, Yūri Fusion Summoned "Antique Gear Ultimate Golem" and destroyed "Mad Chimera", defeating Sora. Before he could seal Sora into a card, he was interrupted by Yūgo and Edo.

Yūto & Yūya vs. Ruri & Serena
When Yūto tried to destroy "Queen" by using Action Card, Serena used the effect of "Parasite Fusioner" to negate the destruction. When he tried to attack "Queen", she used the effect of "Queen" to equip "Parasite Fusioner" to "Dark Rebellion Xyz Dragon", weakening it. She then used "Power Parasite" to equip a "Parasite Fusioner" from the graveyard to "Queen". However, she destroyed it again to prevent "Queen's" destruction and was impressed when Yūto used the same strategy, but she and Ruri took damage from "Phantom Knights Around Burn". Ruri activated "Double Parasitic Rebirth" to equip two "Parasite Fusioners" from the graveyard to Dark Rebellion Xyz Dragon" and attacked but, Yuto evaded it. However, she used "Parasitic Maneuver" to attack again, but Yūto used "Miracle" to halve the damage and protect "Dark Rebellion". Serena used the effect of "Parasite Plant" to equip "Parasite Fusioner" from her Deck to "Queen" and take control of it. When Yūya tried to go an Action Card, Serena tried to grab it first but couldn't, however she noticed the Parasite Monster going inside his ear. The Doctor saw this as well and was happy that he'll become one of his servants and activated "Parasite Fusioner". When Yūya passed out, Serena and Ruri thought Yuya now became like them, but she and Ruri were surprised when he resisted the control. This also shocked the Doctor who wondered why Yuya wasn't under his control. Serena then attacked but Yūya negated it with "Phantom Knights Wrong Magnet Ring". Serena used "Parasite Magic" to use Ruri's "Parasite Discharge" to Special Summon "Parasite Fusioner" from her Deck. Ruri then used "Parasite Generator" to prevent "Parasite" monsters from being destroyed by card effects and treating each "Parasite Fusioner" on the field as two copies of itself. She then used the second effect of "Parasite Generator" to Special Summon a "Parasite Fusioner" from her Deck as many "Parasite Fusioners" from the Graveyard as possible. She brought back two from her and Serena's Graveyards with each one treated as two, bringing to a total of twelve. The Doctor appeared to Yūya through a monitor, telling him how terrifying his Parasite Deck is. He also showed him that Yuzu was already under his control before turning off the connection. Serena and Ruri noticed a sudden change in Yūya and something was wrong when the "Parasite Fusioners" were scared of something. This was proven when Yūya summoned "Odd-Eyes Raging Dragon" and used it's effect to destroy all of their cards and negated the effects of Magic and Trap Cards. Not only that, the dragon was also capable of attacking twice per turn, resulting in their defeat. Serena and Ruri lost their consciousness for a moment, but Serena quickly awoke and then kicked Yūya in the stomach when he approached her before escaping with Ruri. They returned to the Doctor's room, who introduced himself to Yūya and trapped him in a cage and reported to the Professor that Yūya has been secured and left with all four girls. Meanwhile, Academia students surrounded Reiji, Reira, and Yūshō and escorted them to the Professor's chamber, where who told Yūshō that he has been waiting for him while Yūya was watching from the cage.undefined

The Origin of Four Dimensions
Yūri accepted Yūgo's challenge after the latter's insistence for a Duel. Feeling that he wasn't satisfied despite having won so many Duels, Yūri thought it was because he wasn't using his own Deck, so he switched to his original Deck. When Yūgo summoned "Clear Wing", Yūri's desire to destroy everything grew stronger and Fusion Summoned "Starve Venom". The two duelists then entered a synchronized awakening and start shouting to become one. Meanwhile, Leo told Yūshō who questioned his actions that he wasn't a genius since the Solid Vision was just reproduced from existing technology. He revealed to them that it was developed in what used to be the United World or the Original Dimension. He then revealed how the United World had all of the summoning methods and the Solid Vision was already put to practical use there. He wanted to give new possibilities and create a Solid Vision that was more vivid, lively, and flexible, so he used Duel Monsters with it and found out there were perfectly compatible. His research brought forth powerful monsters with mass and he was praised as the person for leading Dueling into a new era. But the technology led the world to ruin due to the people's frenzy and the appearance of a Duelist named Zarc who had evolved Fusion, Synchro, and Xyz with his finest dragons and stood at the top of the Dueling world. One day, Zarc declared he'll destroy the world and Summoned his four dragons to attack everyone. Leo then remembered his earlier superstition that Duel Monsters had souls, which appeared in the worst possible way by giving them real bodies, thereby materializing their anger. Zarc then fused with his dragons, becoming Ultimate Monster: Supreme Dragon King Zarc. The only thing that could fight Zarc, who had godlike power was a Duelist just as strong. Leo felt responsible for creating that demon and couldn't afford to give up, even if it meant sacrificing himself to save his world. When Reiji called it a myth to calm Reira, Leo angrily told him it did, since took place in front of his eyes and that world would enter its final moments because of Supreme Dragon King Zarc.undefined Their conversation was interrupted when Leo was contacted by a Academia member who told him that Yūya escaped from the Doctor's lab. Leo ordered the Doctor to bring the girls as fast as he can, but Yūya has entered his inner chambers. As Yusho tried to convince him not to involve the children and tell him the full story, Leo told Yūshō that Yūya was his son but at the same time was not. Yuzu and her counterparts then appeared behind him in tubes and was told by the Doctor that is ready. When the Doctor wanted to deal with Yūya, Leo thought he couldn't win and tried to talk him out of it, but the Doctor thought it wasn't impossible and expressed confidence in his Parasite work. When he told the Professor that they should be sharing a similar curiosity in confronting challenging research as fellow researchers, Leo turned him into a card as he deemed the Doctor's dangerous thinking and his own past curiosity that caused the Supreme King Dragon's birth. Leo continued his story how he created four cards that could defeat Supreme Dragon King Zarc but were stolen by his daughter Ray, who used them herself to prevent Leo from sacrificing himself. When she defeated Zarc, he was sent to a strange town where only standard Duels happened and recreated the Solid Vision while meeting Yūshō around that time. He revealed that the devil also divided into four due to Ray's sacrifice and became aware of it due to his memories coming back. He then obsessed with the possibility that Ray must be somewhere in the Four Dimensions.

Revival Zero
Leo believed in Ray's survival and found it in Academia, which was Serena due to her spitting image and bracelet. However, she didn't have Ray's memories and remembered that Ray's shadow spilt into four when the Supreme King Dragon divided, so he concluded that Ray was also divided in each of the Four Dimensions. He then revealed that the girls are reincarnations of Ray and plans to revive her, using the ARC Area Project for that purpose. He revealed ARC-V to everyone, which will become the fifth dimension and revive Ray. He asked Reiji to lend his power to defeat Yūya because he was the reincarnation of Zarc himself, saying they have to bury that destructive power to prevent the devil's revival. When Reiji refused to help him and follow his beliefs with Yūya, Leo told him that belief will bring about a ruined world and challenged them to a Duel.undefined

Yūya & Reiji vs. Leo
Leo revealed that he already started the process to fuse the girls back into Ray and the Four Dimensions back into one. When Yūya brought out "Odd-Eyes Pendulum Dragon", Leo remembered it as "Odd-Eyes Dragon" which angered him. His Extra Deck was sealed away when Reiji used "Contract with the Monopoly Seal" to prevent him from using the three summoning methods Reiji used. Leo told Reiji that Yūya is an avatar of Zarc and shouldn't deny it any longer by joining him but Reiji still refused. When Reiji told him that if he didn't start the inter dimensional war int he first place, Zarc won't revive and the Four Dimensions will be at peace. However, Leo still believed that Zarc would revive even if he didn't create ARC-V, especially since Yūya has already absorbed Yūto. Leo then surprised everyone when performed Pendulum Summon, summoning "Spirit Tech Force - Pendulum Governor" and "Spirit Crystal - Salamander Core" that cornered Yūya and Reiji as Leo criticized Reiji's leadership with the Lancers and that their one plan didn't the consider the possibly of the enemy exceeding their expectations. The girls' capsules started to glow, Leo revealed it was only a matter of time until ARC-V starts up and that Ray's revival is at hand. Leo tried to convince Reiji one more time but noticed Yūya's awakening and revealed it was Zarc dwelling inside him. Leo took 2400 Effect damage from the effect of "Entermate Gatlinghoul" and was about to lose when Yūya used the second effect of "Gatlinghoul" to destroy "Pendulum Governor" and inflict damage to "Pendulum Governor's" ATK.undefined Leo used the Pendulum Effect of "Spirit Reactor" to negate the attack by using Reiji's monsters. Leo contacted a Academia member for ARC-V's energy reading and told him to increase the input speed before Zarc revives. Leo continued to gain advantage in Duel, using "Dis-swing Fusion" to stop Reiji's attack, take control of "Hell Armageddon". He was then informed that ARC-V will reach 30% and was happy he was closing in on daughter's revival. He told them to keep adding energy since it should able to accept faster and activate ARC-V as soon as possible. When Yūya brought back "Odd-Eyes" and Summoned "Dark Rebellion Xyz Dragon", Yūri's "Starve Venom" and Yūgo's "Clear Wing" resonated with the two dragons while continue shouting to become one. Yūya brought out "Odd-Eyes Raging Dragon" that quickly cornered Leo. But before he could be defeated, Yūshō used "Binding Swords of Impact" on Yūya, which terminated the Duel, surprising him. He learned that Yūshō used the card he gave to him before and that card was actually a failure due to a bug where it doesn't disappear when the Solid Vision goes offline. He also learned that Yūshō brought the card to remind Leo the basics and thought of using it to bind him but never thought he has to used it on his own son.undefined

Yūri vs. Yūgo, Edo & Kaito
Leo then learned that ARC-V was at fifty percent and left his throne room to watch over ARC-V. As the throne room sealed itself off, Leo said that they can no longer turn back. Meanwhile, Yūri and Yūgo's Duel was intruded by Edo and Kaito who returned to stop them to prevent Zarc's revival. Yūri quickly got impatient and annoyed by their interference and called them scum when Edo managed to return Yūgo to his senses and the former confidently said they will make him smile as well, which offended Yūri. Finally starting his turn, Yūri used "Super Fusion" and Fusion Summon "Greedy Venom Fusion Dragon". He used it's effect to reduce "Destiny HERO - Duskutopiaguy's" ATK to 0 and negate its effect, but Yūgo used the effect of "Crystal Wing Synchro Dragon" to negate "Greedy Venom's" and destroy it. In retaliation, Yūri used the second effect of "Greedy Venom" to destroy every monster on the field and inflict damage equal to their original ATKs. However, Edo used the effect of "Duskutopiaguy" to prevent "Crystal Wing's" destruction and battle damage, saving Yūgo from defeat.undefined Leo wondered how long Yūya's binding will last, wanting to revive Ray first. He stated that by putting the girls into ARC-V first, the world would be one and Ray could revive along with a certain card. He then told the staff to hurry up and increase the life energy. When ARC-V's energy was at sixty percent, they Yuzu transferred into it. Back at Yūri and Yūgo's duel, Yūri Special Summon "Greedy Venom" from the graveyard. Yūgo tried to stop Yūri's loop by taking risks of his LP reduced to destroy "Greedy Venom" without activating it's effect and defeat Yūri in one strike. However, Yūri used the effect of "Predator Plants Drosophyllum Hydra" in his graveyard to banish "Predator Plants Fly Hell" and return "Starve Vemon" to halve the damage and used "Extra Shave Reborn" to bring back "Starve Venom" and negate "Clear Wing's" effects and steal it. He then lower "Clear Wing's" ATK by 500 and destroyed "Clear Wing" by using it's own stolen effect, defeating Yūgo.undefined Now aware that he and his counterparts were the same person, Yūri decided to become one with them again, absorbing Yūgo. Happy that they became one, Yūri felt Yūya's presence nearby and proceeded to go there. Wanting to quickly becoming one with Yūya, Yūri knocked away Yūshō and Reiji who were in his way, but got interested in Yūshō after learning that he was Yūya's father. Yūri finally conceded to Duel Yūshō after the latter determined to avenge his students whom he had carded. After watching Yūri absorb Yūgo and getting close to Yūya, Leo ordered his staff to hurry up and transfer Ruri into ARC-V, so Ray could come back as soon as possible.

Yūri vs. Yūshō
Yūri "Predator Plants Cephalotusnail" while setting two cards, telling Yūshō it was fun enough for him. When Yūshō brought out "Entermate Sky Magician", Yūri thought he used a Magician Deck but learned it was Entermate. Yūshō told him that his trump card was going to be destroyed, and Yūri dared him to try. He used "Dark Seed Planter" to change "Sky Magician's" Attribute to Dark and negate the attack, but Yūshō used the second effect of "Sky Magician" to return "Magician's Right Hand" to his hand and use "Magician's Left Hand" to negate the trap. "Sky Magician" gained more ATK and continued the attack but Yūri used the effect of "Cephalotus Snail" to prevent its destruction and halve the damage. He told Yūshō he failed to destroy his trump card but learned how everything went according to his plan. When Yūshō used "Clairvoyance" to guess what card it was, Yūri reminded him that if he fail, he'll lose. To his anger, Yūshō correctly guessed that his set card was "Super Fusion", forcing him to return it to his Deck due to "Clairvoyance's" effect.undefined At the same time, however, Yūri was pleased by this move as well because no one has ever gave him so much fun before, not even Yūgo. As a reward, Yūri used "Ivy Bind Castle" to negate the effects of Yūshō's cards, prevent him from attacking, and inflict damage for every monster on the field. However, he was surprised when "Sky Magician" escaped from "Ivy Bind Castle" and Yūshō started his counterattack. Finally feeling frustrated, Yūri drew a card that made him even more confident to turn things around. Yūya took this as a mere bluff, prompting Yūri to ask Yūya didn't he want to become one with him. When Yūya refused, Yūri wasn't slightest bit worried since Yūya will wish for it soon since it's their destiny. When Yūshō refuted his claim, Yūri revealed that his prediction about "Super Fusion" was his trump card was wrong, meaning that "Super Fusion" wasn't his trump card. Yūri revealed his real trump card "Transcendental Fusion", that allowed him to Fusion Summon "Starve Venom" and Synchro Summoned "Clear Wing". Yūri used the effect of "Starve Venom" to negate the effects of "Sky Magician" and used them as his own. However, he considered it boring if he only used the dragons' effects, so he destroyed "Magician's Right Hand" and "Magician's Left Hand" to use "Flower of Destruction" to decrease "Clear Wing's" ATK by 3000 and bring back "Starve Venom" and "Fruit of Destruction" to inflict damage to Yūshō and lower "Sky Magician's" ATK by the difference between that and its original ATK. By using the dragons' effects in conjunction with his trap cards, Yūri could repeat the effects for six more times until Yūshō's LP is 0. As he has hoped, seeing Yūshō tormented made Zarc's soul inside Yūya and Yūto reacted again, so Yūri continued his attacks. Meanwhile, Leo had Rin transferred into ARC-V and wished for Yūshō to endure his Duel with Yūri until Ray is revived. Yūri continued his Entertainment Dueling, but Yūshō refused to surrender despite knowing the outcome to preserve his pride as Entertainment Duelist and for Yūya's sake. Annoyed, Yūri interrupted his statement by declaring that Yūya is his and won't give him to anyone. Having enough, Yūya then destroyed "Sky Magician", defeating Yūshō and sealed him into a card. To goad Yūya into fighting him, he showed the carded Yūshō to Yūya while laughing.undefined

Yūri vs. Yūya
Impressed by the sheer anger and power that Yūya showed, Yūri challenged Yūya to a Duel with Yūshō's card and Yūya's life on the line. Yūri Fusion Summoned "Starve Venom" at the start of his turn and told Yūya that his dragon was looking for his comrades, Yūya and Yūto's dragons before setting a card to end his turn. When Yūya started to hesitate after drawing "Smile World", Yūri criticized him and told him to surrender. When Yūya Summoned "Odd-Eyes Pendulum Dragon", Yūri told him their hearts understand each other and was happy when their dragons resonated as Zarc's power and influence became stronger within both of them. Yūri planned to do the same vicious combo that he used against Yūshō to defeat Yūya by summoning "Clear Wing" on his next turn, and felt more excitement from the dragons resonating again when three of them were on the field. Seeing how Yūya was still refusing to fuse with him, Yūri used the effect of "Starve Venom" to negate and steal the effects of "Odd-Eyes", but Yūya used "Starlight Force" to negate the effects of his dragons and change their levels to 4, preventing Yūri from using his vicious combo. Instead, Yūri destroyed Yūya's dragons. When Yūya brought back "Odd-Eyes" and Xyz Summoned "Dark Rebellion Xyz Dragon", Yūri felt more excitement as the Four Dimension Dragons resonated. Yūya tried to use the effect of "Dark Rebellion", Yūri used "Dragon Creeping Plant" to take control of "Dark Rebellion". He told Yūya nobody could stop them now and tempted Yūya to become one with him together with Yūgo and Yūto, who now was under control of Zarc's desire completely. As he watched Yūya and Yūri's Duel, Leo was worried about Zarc reviving if it ends and hurried up Serena's transfer into ARC-V. He was then informed about her transfer and had his throne move away from ARC-V as it activated.undefined With the three dragons on Yūri's side and both Yūgo and Yūto succumbed to Zarc's desire, it became harder for Yūya to resist Zarc's power inside him. Noticing this, Yūri once again tempted Yūya to just surrender and become one with him. Just when Yūya was so close to giving in, Yūya regained his resistance after Reiji reminded him of his father, much to Yūri's disappointment. Convinced that the only way for them to become one is by defeating Yūya, Yūri began his attack. As he watched the Duel between the two went on, Leo activated Isolation Dome that trapped the two duelists and everyone in Academia in a dome separated from ARC-V until Ray and the four cards necessary to defeat Zarc were revived. However, Leo found that Ray has yet to be resurrected since there was no sign of a life signal within the core, wondering what happened even though all the four girls and the four dimensions were already integrated. Yūri succeeded in cornering Yūya by gaining advantage in Action Card, destroying every Action Card that Yūya got to protect himself from Yūri's attack. Yūya started to lose hope of winning until his friends encouraged him to focus on winning. Yūya was able to take back "Dark Rebellion" and take control "Clear Wing" by using "Entermate Trap Mimic's" effect that able to destroy and then mimic "Dragon Creeping Plant's" effect. Knowing Yūya will use "Dark Rebellion's" effect to decrease his dragon's ATK and then deliver a finishing blow, Yūri activated his two set trap cards to stop any of Yūya's monster to attack. Unfortunately, Yūya used "Entermate Flat Rat's" effect to return "Odd-Eyes's" ATK, allowing it to destroy "Starve Venom" and depleted all of Yūri's remaining LP with its Reaction Force as Yūri accepted the attack with a laugh.

Revival of Supreme King Dragon Zarc
As Yūri was laying defeated, he expressed his satisfaction that Yūya was the first opponent to defeat him since Yūya was his counterpart. As promised, Yūri gave Yūshō's card to him and resigned to be absorbed into Yūya. However, it turned out that right after the Duel ended, Zarc has taken complete control of both Yūya's body and soul. With all of his reincarnations present, Zarc proceeded to absorb Yūri and Yūya and fused himself with the four dragons using "Astrograph Magician", reviving himself as Supreme King Dragon Zarc.

Technology
Their technology is advanced enough to create brain scanners that can access to one's memory. They are also shown to have interdimensional travel technology, as well as abilities to materialize Duels and technology to seal any human into cards.