From his first appearance, it is clear that he is quick-tempered and behaves quite arrogantly. Even his first conversation with Tanjiro begins with him insulting Nezuko by calling her uncouth. He is usually shown with a sullen expression, unless he is talking about Tamayo. He only cares about Tamayo and hates it when others get in the way of his time with her. Although he was literally hundreds of years younger than her, he still loved her and was ready for anything. whatever that meant to him.