Yuma has a laid back personality and is not very knowledgeable about Japanese customs, being from another world (despite having a Japanese father), leading to some run-ins with rough people. He is logical, advising Mikumo to stay away from the trion Battle Soldier rather than save the students as Mikumo could die. He seems to be aligned with Border's cause, fighting against Neighbor forces. Despite his happy exterior, he is actually deeply depressed due to his father's sacrifice to revive him.