Why you? You're the one who summoned me.

[It doesn't make sense, to pin the blame for what the other had done on him. He had been desperate enough to summon a demon, and to summon a demon without any sort of bargaining chip other than his life.

The kindness is that Kazuya didn't eat him. The kindness is that at the end of it, he won't consume his soul.

The kindness is that Kazuya will keep his word, and not play dirty to end the others life early to breach the contract.]

Your suitability is that you needed protection, and I offer that. That your body can support such a thing is also attractive.