Yūya Sakaki/Relationship

Yūshō Sakaki
Yūya greatly loves and admires his father and dreams to become a professional Entertainment Duelist like him. It is also through Yūshō's dueling Yūya developed his belief that dueling is for fun and makes people happy. Despite his father's sudden disappearance, Yūya continues to respect and admire his father, believing there's a reason for his disappearance and dislikes when someone make a fun of his father.

Yōko Sakaki
Yōko is Yūya's mother. Although not as close as Yūya did with his father, Yūya is also in a good relationship with his mother like a normal mother and son. Yōko understood how her son was feeling when his father disappeared and is supportive of Yūya's dream to become a professional Entertainment Duelist like his father. She would help and take care of Yūya in any way she can when he is in trouble, as shown when Yūya was unconscious for two days and challenged him to a Duel to help him regain his spirit. However, Yūya is often flustered whenever his mother's fondness for cute boys get the better of her. When this get the better of her, she doesn't hesitate to cheer them such as Michio and Dennis rather than her own son. When Sora successfully pleased her with his sweet-talk, Yōko takes care Sora more, almost not minding Yūya.

Yuzu Hīragi
Yūya and Yuzu are childhood friends. Yuzu is supportive of Yūya and would help him whenever he is in trouble and defending him when someone make insulting him. Yuzu also acts as a "straight man" in a comedic act with Yūya, usually beating him with her paper fan when he angered her in any way. Behind this, she harbors feelings for Yūya more than just a friend. This feeling is made apparent when Yuzu blushed when Sora mistook her as his girlfriend, she blushed heavily when accidentally hugged Yūya that caused her to push him away, and jealous if Mieru makes advances towards him or calling him "darling". Unfortunately for Yuzu, Yūya is oblivious of her feelings towards him and so far only think of her as his close friend, furthered by the fact that he protested at the prospect of dating with crude strong girl like Yuzu when Sora mistook her as his girlfriend. Her feelings for Yūya is also what drove her to become stronger so she can protect him and the others. Out of Yūya's friends in the series, Yuzu is the one who is mostly beside Yūya.

Yūya, on the other hand, is also supportive of Yuzu and is grateful for all her help for years. To Yūya, Yuzu feels like an older sister and he cherishes her greatly. She is someone who has always been with him, an irreplaceable existence. When she is depressed, Yūya always gives his encouragement to steer her spirit. Yūya's bond with Yuzu is shown to be very deep, as shown during the aftermath of Battle Royal, Yuzu is the one whose well-being Yūya cares the most as he states how Yuzu is the one who is always by his side from the very beginning and it was also thanks to her he was able to grow his Pendulum Summoning. During her Riding Duel against Chojiro Tokumatsu, she managed to rejuvenate Yūya's spirit with her entertainment duel.

Noboru Gongenzaka
Yūya and Gongenzaka have been friends since they were kids and share a very close bond. After his father, disappeared Gongenzaka always defended Yūya from bullies and is very protective of Yūya. Not only defending him from bullies, for years, Gongenzaka also helped Yūya on finding an opponent for Duel with his dōjō's connection, something that Yūya is very grateful for. His friendship with Gongenzaka made Yūya at first hesitated when he has no choice but to duel with him to enter Maiami Championship out of fear it would make Gongenzaka lose his chance to enter as well. Gongenzaka cares for Yūya and worry whenever something happened to him, usually giving him a hug after he is confirmed to be fine.

Futoshi Harada, Tatsuya Yamashiro, and Ayu Ayukawa
Yūya acts as a older brother figure to the three of them, continuously supporting them to improve their Dueling skills. In return, Futoshi, Tatsuya, and Ayu admires Yūya whom they called "Yūya-onīchan" and also supporting him in return. Though, they sometimes also like to tease Yūya in some way, one of such is how Yūya is oblivious about Yuzu's feelings towards him.

Shūzō Hīragi
Yūya respects Shūzō as his teacher and his father's close friend, usually asking him for advice when he is confuse how to proceed with his Duel. Like everyone else, Shūzō has high hopes for Yūya to follow his father's footstep and succeed him as an Entertainment Duelist, seeing him as one of his best students. Shūzō sometimes also gives Yūya an errand such as picking up Yuzu when she spent most of her times to train Fusion Summon with Sora.

Sora Shiun'in
Yūya at first was annoyed and flustered when Sora followed him everywhere and insisted for him to make Sora his apprentice, but they eventually get along well. Yūya thinks Sora as a dear friend and cares for his well-being, defending him when he appeared to be in trouble and expressed concern when he was injured. Sora, on the other hand, admires Yūya after he saw his match and insisted to be his apprentice, but then decided to become his friend after he lost in the Duel. Sora has shown great interest towards Yūya for many of his achievements in Duels that he claims to always be beyond his expectations. However, while Sora truly thinks that dueling with Yūya is genuinely exciting, he claimed that he was just playing around as his loyalty to the Academia and their goal is more important to him than their friendship. Despite this and seeing Sora change people into cards in front of his own eyes, Yūya still considers Sora as his friend and is determined to make Sora smile and enjoy Dueling like when they first Dueled.

Yūto
Although they both had only met for a short time, Yūto developed a strong trust towards Yūya who shares the same belief as him. This is what made Yūto entrusted Yūya with his "Dark Rebellion Xyz Dragon". Yūya, on the other hand, was initially wary and skeptical of Yūto, but Yūya eventually understood that Yūto actually doesn't want to hurt anyone. Even though Yūya doesn't understand what Yūto expected from him, Yūya resolved to make people smile with Dueling like Yūto told him to. Yūto's last words to him occasionally became a reminder of Yūya's Dueling belief. After experiencing the possession caused by Yūto's anger and sadness, Yūya started to understand Yūto's suffering and opted to believe in Yūto who wishes for peace instead of blaming him for the consequence of his brutal Dueling method.However, Yūto sharing his memories and desires with Yūya has severely traumatized him as shown by his reaction to the memories of Heartland being invaded and all the people being attacked. Yūya developed what would appear to be a case of PTSD as shown by his reaction to being in the Heartland field after the invasion. Despite this, without the two of them realizing, the two formed a strong bond with one another similar to that of brothers. While Yūya's promise with Yūto became one of Yūya's main motivations to continue dueling, Yūto trusted Yūya as a comrade that will never betray his friends. Yūto is also shown to be protective of Yūya, seen when he took control of Yūya's body when he was cornered during his duel with Isao (though this method upset Yūya for some time) and defended him from Shun's accusations while merged with Yūya. In return, Yūya is also protective of Yūto, immediately telling Reiji to stop when the latter was about to bring up the tragedy of Xyz Dimension, knowing it traumatized not only Shun, but also Yūto within him.

Reiji Akaba
Reiji is by far, Yūya's strongest rival in the series. At first, Yūya held degree of respect towards Reiji for his dueling skill and for defending his father when Yaiba and Hokuto mocked him. However, any inch of respect Yūya had towards Reiji was immediately lost when Reiji revealed that the Battle Royal was a test to recruit Lancers and that he plotted for his friends to fend off the Fusion Dimension invaders, which resulted in many of them being sealed in cards. Yūya now held a spiteful grudge towards Reiji and only blamed him for the loss of his friends and Yuzu's disappearance, and even tried to punch him out of anger. This was enough to make Yūya Dueling solely to make Reiji repent for what he had done, not even using his Entertainment Dueling against Reiji. After his lost against Reiji, Yūya has yet to forgive him, but begrudgingly work together with him to save Yuzu and those who have been turned into cards. Despite having accepted to join the Lancers, Yūya continues to be hostile towards Reiji, and his opinion of him further soured when he learned how he treated Reira.

Shingo Sawatari
After being defeated in his first duel with Yūya, Sawatari formed a rivalry with Yūya and vowed to defeat him. Due to Sawatari stealing his Pendulum monsters and kidnapping his friends, Yūya in turn didn't like him at all. However, this seemingly changed throughout their second duel in the tournament where both duelist showed respect to one another. After winning a second time, it would appear Sawatari and Yūya became friends with one another (similar to how Jūdai and Manjōme from GX did) and, while they sometimes get annoyed with each other, they seemed to have gained a lot of respect towards each other. This is proved by how Sawatari stormed Reiji's office in an attempt to watch Yūya preform in the tournament after the video feed was cut during the invasion and how he showed sincere sympathy towards Yūya after he lost Yuzu. Yūya also showed surprise and concern when Sawatari lost to the Security in a one-turn kill. Their more friendly relationship is shown later on in the Synchro Dimension when Shingo told Yūya how excited he was to show off their Entertainment Dueling to the Synchro Dimension during the prelude of the Friendship Cup in front of the Executive Council.

Serena
When he first saw her, he mistook her for Yuzu due to their similar appearance. Yūya and Serena generally get along well, given their shared goal of rescuing Yuzu, but Serena's impatience and hot-headed nature tend to clash with Yūya's more patient and pragmatic nature.