Yūri/Relationship

Leo Akaba
Yūri appears to be very loyal to Leo, obeying all of his commands. This loyalty seems to be originally came from the fact when he was a child that unlike the others who feared Yūri, Leo acknowledged and accepted his skill and allowed him to do Duels that he likes and turn his opponents into card once the inter dimensional war begin, something that made Yūri happy. Yūri will do his best to fulfil Leo's given order and didn't dare to disobey it. As such, despite wanting to turn Yuzu into card, he didn't do so because Leo had ordered him to bring her back unscathed. Despite his origin, Yūri seems to be one of Leo's most trusted Duelists amongst Academia, as he personally gave only Yūri alone the order to capture Yuzu and her dimensional counterparts, something that only a few Academia Duelists knows. And Leo only ordered Yūri to fulfil the mission, proving that Leo is confident in Yūri's skill.

Unfortunately, Leo's teaching consequently caused Yūri's mind to become so warped from carding many people under his order to the point he no longer care about Leo and his goal, only wanting to card people for his own enjoyment. From then on, Leo sees Yūri as nothing but Zarc's reincarnation that will destroy the world and determines to put a stop at him and his counterparts at any cost.

Yūgo
Yūri first met Yūgo when he kidnapped Rin, Yūgo's childhood friend. Since then, Yūgo bears a strong hatred towards Yūri and traveled from one dimension to another to hunt him down. Yūgo's obsession on Dueling him quite annoyed Yūri, who only saw Yūgo as bothersome and didn't worth his time, usually ignoring Yūgo when the latter challenged him to Duel and instead continuing his mission. Yūri's interest in Yūgo started to spark when he found out that Yūgo had defeated Serena, and finally agreed to his challenge as he now considers Yūgo capable of providing more fun to his hunting game. After he won his Duel against Yūgo, Yūri expressed how much fun he has when duelling the former, regretting that he didn't do it sooner and treated him as a nuisance until now.

Yūya Sakaki
Yūri and Yūya initially didn't interact much until much later in the series. Yūri came to got interested in Yūya after coming into realization that he and Yūya were originally a same person and quickly developed a strong obsession to merge with Yūya. His desire makes him possessive of Yūya, exclaiming that Yūya belongs to him and he won't hand him over to anyone.

To merge with Yūya, Yūri has no hesitation to get rid of anyone who get in his way and will do cruel acts to lead Yūya into merging with him, going as far as tormenting Yūshō not only to defeat his opponent but also to drive Yūya into Zarc's influence. When dueling him, Yūri continuously tries to tempt Yūya into merging with him by taunting while attacking him. Yūya quickly developed deep resentment against Yūri after watching his father tormented and carded by him, enough to enrage Yūya that he succumbed to Zarc's influence with the only thought of defeating Yūri.