Ridiculous D&D contrivances

[Godskook]

Casting a Good spell is a good act.

That comes with the prerequisite of being good, I thought. Either way, how would a Demon have a 'good' spell on his spell list?

@Amesoeurs

Um, bringing virtue into this just muddies the water. Either its a synonym for 'good' or its a list of things that evil-doers can do.(Demons can be patient, for instance. A clean demon rarely leaves clues behind. A courageous demon isn't unimaginable)

Let me rephrase the challenge. Name one 'good' act that a demon can be compelled to do on threat of death.

Deity worship wouldn't work, since no 'good' deity would accept compelled worship, and any contrivance brought up to make that happen would be less believable than the demon's nature to begin with.

(And summoning doesn't work either. See Constantine(the movie) for an explanation)