"Keep moving till you've given it all you've got and when you fall, get right back up again!" Yuma is a hasty, energetic, and cheerful young boy who likes to challenge himself to do anything that seems impossible, which he normally fails at. Undaunted by his failures, he states that doing these challenges gets him fired up and will eventually accomplish what he sets out to do. He calls this challenge his "Kattobingu" spirit ("feeling the flow" in the dub), which his father taught him. Even Yuma would sometimes doubt himself when depressed.Forthright and honest, Yuma is shown to assist others if they are in trouble, despite their protests. Yuma believes Duelists cannot be bad people and believes a Duel to be a clash of souls. Due to his short-temper and stubbornness, Yuma is easily annoyed, and frequently clashes with Astral. Yuma tends to disobey Astral's instructions when they Duel, which leads to him making mistakes. He only starts obeying when he is about to lose, as he believes the Duels are his and listening to him would mean he needed help to win.
When they first met, Yuma had mixed feelings about Astral when all he did was tell him how to Duel during his Duel with Shark. Though Astral was insightful and was always thinking about what his opponent would be capable of doing, Yuma ignored his advice and continued playing his way. Eventually, Astral figured out a way to have Yuma listen to him and over time, Yuma began trusting Astral more and more with each Duel. They are shown on numerous occasions to be able to talk telepathically. At times, Yuma didn't openly admit that he was worries or care about Astral, usually feigning anger and yelling at him, which only makes Astral smile because he knew Yuma's true feelings. In dire situations, Yuma openly showed concern and proclaimed he would do anything to protect him from danger. It shown that Yuma deeply cares for Astral as he couldn't believe Astral would leave and as he cried for his death. Astral has shown many times how much he cares about Yuma, willing to give up his life for Yuma's safety. Astral has also been seen smiling more since Yuma told him that he is his friend, and encourages Yuma to never give up. Later, it was revealed that Astral has been teaching Yuma how to Duel, since one day he'll disappear and Yuma will have to fight alone. He also said that when he disappears, he would want to leave proof that he exists in Yuma's memory and heart. After Astral was revived, Yuma was greatly relieved as he cried tears of joy.