He is heartless, he is unlike his old self. He used to be kind, helpful and caring but now he shows no mercy towards humans. He has no interest in fighting weaklings and he only devours strong slayers that he had came across. He doesn't care of he's fighting a man or a woman, because countless men and women didn't make it alive when they're fighting him. He is the strongest, the real demon. He can be a demon king when he wants to kill Muzan, he can be whatever he wished to be.