A mysterious boy interested in Yuya's Pendulum summoning, and soon becomes his apprentice. Sora is shown to be a huge fan of Yuya, to the extent of obsession. This is shown when he constantly follows Yuya around, wanting to see Pendulum Summoning first hand. At first Yuya declines, causing Sora to spy on Yuya and continuously bother him until he gives in. Sora has also been shown to use his cute appearance to win others over to his side and get his own way. However, it does not seem to work on Yuya, who only agrees to Duel with him if Sora stops following him around. Sora is also extremely childish and persists until he gets his way. Sora has a habit of misunderstanding situations, often asking "Did I get it wrong?" in response to other peoples' reactions.
Sora also shows exceptional knowledge of Duel Monsters for his age, including the different styles of Summoning and can strategize accordingly. However as such, he does not take Dueling seriously unless there is a Duel or Duelist that excites him, and ultimately, this is what motivates Sora: his own entertainment. He is also shown to be obsessed with sweet food items or candies to the extent that he is rarely seen not eating them, even to the extent that he eats during lessons.
During his first Duel against Shun, Sora is revealed to be a soldier of Duel Academy, a "Duel Soldier" training facility in the Fusion Dimension. As a soldier of Duel Academy, he swears loyalty to Leo Akaba and his plan to "unite the dimensions" despite his friendships with Yuya and Yuzu.
Due to his training as a Duel Soldier, Sora had no friends before coming to Standard, thus, making Yuya and Yuzu his first genuine friends. With encouragement from Yuya and Yuzu, Sora eventually realized he was hurting people and reluctantly abandoned his old ways. Since then, he has formally turned his back on Duel Academy and becomes an unofficial ally of the Lancers, working to keep Serena and his first friends safe.