The witch hunt

Demons and humans are hunting for witches but they are hunting them for different reasons.. Demons want their blood to transform into human and to make sure no one can be more better/powerful than them, while humans think the witch's power would go into the body of who has defeated the witch. However, one demon and one human refuse to believe these things.
P.S,
this is a gacha story, you can imagine it not as one if you would like because I ain't gonna stop you.