The main character is the devil who always gets what they want but these desires always come with a price they do not want to pay but the devil can not seek anything else without paying a price that they do not want to pay.
It becomes a vicious circle until the devil decides to help others get what they want instead...and instead of the devil paying a price they do not want to, the target of their humanitarianism ends up paying.
So the devil finds a way to get what they want without ever trying directly by instead helping others get what they want until it gets the devil their desires as a secondary consequence of the request....
Only to find out a tertiary consequence to this effort ends up doing so much good over time that the devil loses their powers and is forgiven without condition to enter the pearly gates against their will...
The most depressed angel in heaven. That's when things get interesting.