God, Please Make Me a Demon!

At a glance, high-schooler Moran Baek appears to be a beautiful girl who's perfect in every way... or so it would seem. In reality, she is an exiled demon who has been trapped in a human body for over 5,000 years. When she learns that she is still unable to use her demonic powers despite finishing her exile, Moran despairs and struggles to find a way to become a demon again. One day, she accidentally discovers that doing a good deed restores her powers, and sets out to find a way to keep doing good deeds so she can return to her devilish ways.

(Source: Tappytoon)