Extremely volatile, severe, his sense of humor is twisted. His greatest desire is to protect a human woman whom he welcomed into his palace. He pretends to hate her to hide his feelings, but deep down he is too possessive and clingy. He will do everything possible to protect his human from any creature, he will even die to protect her. He wants to stay with her for eternity and if necessary he will force her to be with him at any cost. Klein is a violent and severe demon, but with a noble heart.