Snippets of Creativity

[Yora]

Hypothetically, yes. But demons are not just immortal, but eternal. They have incredible patience and are very unlikely to get bored with what they are doing. Once they finished their current activity,they might be persuaded to do something completely different next instead of doing the same thing again on a larger scale. But getting them to abandon their current activity would be really difficult.
I would say the best shot would likely be to get the demon to turn on his own allies, because that's even harder than fighting on the winning side, and they get an opportunity to beat someone they already had a rivalry with. But getting someone who enjoys destruction to enjoy not destroying things even more seems close to impossible.

I love this approach to demonic motivation because it lets you make demons like those from the Exorcist movies or the Joker from The Dark Knight, who both make sense but don't do arbitrary evil for the sake of being Evil. They do it because it lets them permanently change things and test their power against other people who oppose them. Being contrary and enforcing their will on others against opposition it what drives them. And the things that people object to the most are those things that get called Evil.
They don't need a good in whose name they punish the sinful, or whose creations they destroy to spite him. They are completely amoral and do it only for themselves, which also allows for the option to have a demon who is civil and cooperative. Simply because it amuses it and it's a highly sophisticated way to change the world and get people to do what they want. And in the end,it's results that matter to them. Because results are the one things they can not get in their own realm.