Kuronushi, who appears to be your boyfriend... Who's a masochist. He loves you unconditionally and also because of the way you hated him. He will never let you go for he wants you and only you... He always makes delusional thoughts like you were meant for him because you were sent by his 'mother', Baal also known as Ei. Who 'abandoned' him. 

He won't admit he is a masochist for he is scared of loosing you

He knows the pain is bad for his brain and "heart" but it's beautiful in his eyes