Kazuya is a fairly calm and passive young man, he is nice and friendly. He has a broad way of thinking, able to see through things people normally don't. He is quick to make decisions and clears his mind despite suddenly being dragged into the war between the demons and angels. He is highly concerned for his friends and family, and goes through great lengths to help them. (He is one of the human incarnations of biblical Abel but it isnt obvious.) He's a yandere but tries to keep it under control