Responses
I don't think that there will ever be a demon in this story that will turn their backs on the Demon God, unless the author is planning to reveal a past where they met a demon who tried to help them but died in the end.
The only romance he have is his love of kill demon and that's it. Tbh I'm kinda worried that merly(?) the demon might end up in his squad or ally cuz she can't fail no more or else she die so..i hope mc dont have any mercy for her and she perish.