Yūya Sakaki/Relationship

Yūshō Sakaki
Yūya admired his dad for his Entertainment Duels and the way he performed. Not exactly much is known about their family relationship. But his father thought many things that Yūya uses to this such as looking forward.

Yōko Sakaki
Yūya's relationship with his mother is quite difficult to understand sometimes. Sometimes, his mother tells other (characters) about Yūya and his father, being serious and nice about his son. At home, she usually has a typical mother-son relationship. After Sora Shiun'in start coming to their home, Yūya was being sold out for Sora even though Yūya is her son and yet she takes care of Sora more.

Yuzu Hīragi
Yūya and Yuzu are childhood friends. Their relationship is that of regular friends in many anime. Yūya can be bad towards at Yuzu at times and Yuzu usually gets pissed about it. Though, it could be hinted they could have a romance relationship as they knew each other for a long time and get blushes at times such as when Yuzu didn't realize she was hugging Yūya.

Shūzō Hīragi
Yūya respects him. Shūzō could be too hot-blooded at times, giving Yūya bad/weird impressions. Shūzō helped Yūya come back to his usual self when he was shocked by the fact there is someone besides that can Pendulum Summon.

Yūto
Yūya and Yūto have never met each other in the story so far, but they share same/identical faces. Yūto even showed traits that were similar to those of Yūya's such as their ace monsters (sharing the same Attribute, Type, ATK & DEF), and Yūto also shares some things that Yūya have said. They could be the same person or each others' alternate versions from different dimensions/timelines, though it's unconfirmed the two finaly meeting in episode 35.