Yūgo/Relationship

Yūto
Yūgo has an antagonistic relationship with Yūto and he travels from one dimension to another to find him so he can defeat him. Their animosity towards each other was strong enough to make them act first before thinking further. This turns out to be a misunderstanding between the two of them. Yūgo mistook Yūto as Yūri, who kidnapped Rin, while Yūto mistook Yūgo as one of Academia Duelists when the latter challenged him instead of answering his question on their first meeting.

Rin
Rin is Yūgo's childhood friend. They both are orphans who grew up together. Both shares the same dream to Duel Jack Atlas one day, building Yūgo's D-Wheel together. Rin acts like a mother for Yūgo, always scolding him for his recklessness and short temper that often gets him into trouble, which sometimes annoys Yūgo. It was shown that Yūgo harbours feelings for Rin, blushing and grinning happily when Yuzu thought that Rin was his girlfriend. His affection for Rin is also expressed when Yūgo attempted to hug Yuzu because he mistook her for Rin. While it was still unknown whether Rin return his feeling or not, both are clearly close to one another. Yūgo's feelings for Rin is what driving him to find Yūri and save Rin.

Yuzu Hīragi
Yuzu was saved from Yūri by Yūgo, who mistook her for Rin. When they were in the Synchro Dimension, Yūgo and Yuzu built a quick friendship. Yūgo attempts to help out Yuzu with the issue of the Interdimensional Domination, such as trying to warn the citizens about the Fusion Dimension and getting annoyed when others laughed at her, he also signed her up for the Friendship Cup, believing it would be a good idea to convince others about the threat. Yuzu also shows concern for Yūgo and able to relate herself with him because of the absence of their mother in their lives. However, she has been frequently annoyed by Yūgo, due to him mistaking her for Rin and his straightforwardness, causing her to hit him with her fan, or threatening to do so. When Yuzu lost against Sergey and crashed into a building, he and the other contestants were horrified.

Serena
Upon meeting Serena for the first time, Yūgo mistook her for Rin and constantly tried to hug her, despite her constant rejection. His confusion actually affected his performance initially in their Duel, but he soon got himself on track. Yūgo finds Serena's by-the-books strategies to be the wrong way to Duel, explaining to her the justification of his perspective on Dueling.