The Awakening

The Awakening (覚醒 Kakusei), also known as Berserk Mode, is an unofficial term used to refer to the state of mind that Yūya, Yūto, Yūgo, and Yūri occasionally enter.

Effects
This ability causes Yūya and his dimensional counterparts to go into a state of rage, signed by their glowing eyes. This usually occurs in a Duel invoking the Four Dimension Dragons where the dragons seemingly overtake their owner's mind, or when the user is sufficiently angered, and its activation is accompanied by an excruciating amount of pain. While they are awakened, they are willing to harm or destroy their opponent in order to win the Duel. When they regain their senses, they generally have no knowledge of what happened while they were awakened. The only exception was Yūgo, who is able to retain a glimpse of his memory in such a state. If they enter the Awakening while being merged by one of their counterparts, they become vulnerable to being influenced counterpart's own memories and desires.

Notably, Yūya's Awakening is slightly different from Yūto and Yūgo's. Originally, instead of going into a blind, homicidal rage, Yūya is collected and cold, speaking no more than necessary. However, during his Duel against the Obelisk Force, Yūya instead acted on Yūto's deep hatred for the Fusion Dimension for invading the Xyz Dimension and proceeded to defeat them ruthlessly. Additionally, his hair becomes wild and his pupils glow red instead of his entire eyes; in extreme cases, his hair sticks upward, his pupils glow white, and he is surrounded by a dark aura. Because he absorbed Yūto's soul and merged with it, Yūto can indirectly take control of Yūya, which triggered the state, although both souls become increasingly vulnerable to a darkness born of Yūto's hatred. Once aware of the circumstances, however, Yūya has become capable of breaking out of this mode by sheer force of will. At one point, Yūya was capable of controlling this state. So far, the only instance he did so was during his Duel against Duel Chaser 227, in which even though Yūya was filled with anger and his main objective was only to defeat his enemy, he has full control of his anger, making him less violent than before.

After the awakening, each counterparts may have little to no recollection of what happened while they are in the state.

This mode can also be forcefully triggered by interference from outside their dragons or emotions. The notable example of this is when Yūya entered this state not because of his dragon or sufficiently angered, but because of the mind-control chip that Roget has placed that interrupted the nerve of his brain, causing his state of mind turned into turmoil.

Each counterpart's eyes glow a different color when awakened: Yūto's eyes glow blue, Yūgo's green , Yūya's red , and Yūri's purple.

Stages
In Yūya's case, there are four stages of Awakening. Each of this stage capable of progressing into the next with enough time and each time it progresses, Yūya's Dueling skill increases significantly. The four stages are:
 * First Stage: Yūya's irises barely glows and unlike the other stages, Yūya is not filled with anger or contempt or any negative thoughts and quite in control of himself while also becoming more serious and confident. This stage is only shown once during his Duel against Strong Ishijima. As he entered this state, he also gained the ability to Pendulum Summon. Like other stages, however, Yūya has no recollection of what he has done while in this state.
 * Second Stage: Yūya becomes collected and cold, speaking no more than necessary. Additionally, his hair frizzled and his voice deeper, both his iris and pupils glow and mute any natural shine to them. Yūya's Duelling becomes more straightforward in attacking his opponent. When under influence by the darkness, dark aura also surrounds his body for a moment before it dissipated.
 * Third Stage: Yūya's hair sticks upwards, his pupils glow white, and the influence of the darkness is stronger, resulting Yūya's body being constantly surrounded by a dark aura. While Yūya's Duelling skill increased, he becomes vicious and even sadistic, enjoying to inflict harm on his opponents. He is also capable of unleashing powerful shockwaves that are beyond normal for a person originating from the Standard Dimension. This stage also gives Yūya a strong tolerance of pain, able to stand up and barely feeling hurt even after he continuously got attacked.
 * Fourth Stage: Unlike the four previous stages, this stage requires all of Yūya's counterparts to be present near him or at least on the same area. Yūya pupils will glow even brighter and the dark aura surrounding him is darker and stronger than before. Yūya's anger in this stage grows to an almost primal rage, he become impervious to reason. This stage takes such a toll on their bodies and minds that their eyes becoming dull and empty as the glow fades, and all of them pass out afterwards. Anything he is in contact with also gain black aura, in the same manner as Yūya. Similar to the third stage, this stage also gives Yūya a strong tolerance of pain, able to stay conscious for a duel after and while being electrified.

Pre-Maiami Championship
The Awakening initially appeared during Yūya's Duel with Strong Ishijima where, while his eye's didn't glow, he became serious and calculating and proceeded to defeat him and Yūya couldn't remember what happened when he first Pendulum Summoned. The Awakening appeared again during the Duel between Yūto and Yūgo. When Yūto Xyz Summoned his "Dark Rebellion Xyz Dragon" and Yūgo Synchro Summoned his "Clear Wing Synchro Dragon" their eyes glowed. After being reminded by Yūya that he didn't want to hurt anyone, Yūto came out of his Awakening, but then lost to Yūgo who was still awakened a moment later.

Maiami Championship
Later in his Duel against Isao Kachidoki, Yūto appeared in Yūya's mind and the two merged, causing Yūya to awaken and duel ruthlessly. He summoned his Pendulum monsters and used them to summon Yūto's "Dark Rebellion Xyz Dragon" and won the Duel brutally. When Yūya regained his senses, he was met with concerned stares from the audience and disdain from Isao causing him to wonder what he had done.

During his Duel against Makoto Takeda and Ken Umesugi, "Dark Rebellion" appeared in Yūya's mind and he would have entered the Awakening had his ally, Dennis Macfield, not managed to bring him back to his senses before it fully consumed him. Yūya proceeded to summon "Dark Rebellion" and was able to remain in control for the remainder of the Duel and use it's affects to win.

After seeing the Knight of Duels students being turned into cards by the Obelisk Force, Yūto's memories of Heartland's invasion and vengeful hatred towards the Fusion Dimension flooded Yūya's mind, triggering Yūya to enter the Awakening again to take revenge on them. This time, Yūya's Awakening took on a whole different level; Yūya became more brutal and even enjoyed inflicting damage to his opponents. During the Duel against the Obelisk Force, Yūya progressively became more malicious and violent, becoming surrounded by a dark aura, and ultimately he summoned "Odd-Eyes Rebellion Dragon" to defeat them all at once.

After winning the Duel, he continued to his next target, Sora Shiun'in but was restrained by Gongenzaka, Mieru Hōchun, Michio Mokota, and Teppei Tairyōbata. Yūya only kept on yelling violently in pain until he snapped out of his awakening. Mieru was able to determine that there were two hearts within Yūya, along with a terrifying darkness. Yūto's soul was the one who initially triggered the Awakening, but the darkness eventually took over both souls and worsened it.

When Yūya saw his friends being turned into cards by the Obelisk Force one by one, he awakened once more and chased after Sora. After reaching Sora, however, Yūya recalled Yūto's words and managed to calm down, negating the state.

Goaded by Reiji Akaba in their duel that brought up the memories of his carded friends and tragedy of Heartland, Yūya briefly evoked this state but able to prevent himself from entering it by his sheer force of will.

Friendship Cup: Round 1
He later briefly enters the state in his Duel against Duel Chaser 227 and though he snaps out of it soon enough since he was able to control his anger, but still retains the serious demeanor throughout the rest of the duel.

During the rematch between Dennis and Shun, Yūya briefly awakened again after learning about the former's affiliation with Academia and sensed Yūto's hatred and anger within him that reacted the moment Dennis' true colour was revealed, but he snapped out of it after remembering his own belief and the promise he made with Yūto.

Friendship Cup Semi-finals
During his match against Crow, the electrical shock chip that Roget has placed inside Yūya's helmet made his mind unstable and triggered this state. His synchronisation with his dimensional counterparts also led them to enter the same state. The state was invoked again when Yūri, the Obelisk Force, and Yūgo arrived at Yūya's location. With Yūya controlling "Odd-Eyes Pendulum Dragon" and "Dark Rebellion Xyz Dragon" in his Duel with Barrett and Yūgo and Yūri summoning their "Clear Wing" and "Starve Venom Fusion Dragon" respectively, all of the Four Dimension Dragons were in play at the same time, causing Yūya and his counterparts to awaken and synchronize again. As the dragons began roaring in each other's presence, Yūya and his counterparts began speaking of becoming one. A huge dimensional hole appeared in the sky afterwards and his counterparts soon began heading towards it. before the unification process could begin, Yuzu arrived and sent Yūri and Yūgo away with her bracelet ending the process and the Awakening.

Trivia

 * Unlike his dimensional counterparts during the Awakening, Yūya's eyes doesn't glow entirely, only his pupil glows.
 * Yūya is so far the only one to nearly reach the Awakening by another dragon's influence instead of his own dragon.