Kensei is a serious and decisive individual, though he is easily annoyed and is rather temperamental, often to a fault. He is greatly annoyed by immaturity. He is most frequently irritated by Mashiro's childish behavior, once noting that she has the uncanny ability to aggravate him even when she is asleep. His aggressive behavior is particularly noticeable in combat. At one point, he confesses that he is not mature enough to hold back, even against a child. Despite this, Kensei is at times a caring individual, though his attempts at being kind are often offset by his aggression, such as when he tries to cheer up a young, tearful Hisagi in a manner reminiscent of a military drill sergeant.