consider:
demons deal in contracts, angels deal in relationships.
a demon earning redemption through genuine care and protection, even if it violates their contract.
an angel falling through trying to control and manipulate someone - they may love them, but not enough to let them change or leave.
idk I just like the idea of love being both a force for good/healing and a force for someone's downfall. the parallels. the symbolism. Why don't we talk about/consider the Redeemed Demon, if we can see the Fallen Angel?