Fallen angel
Harut and Marut: Their sin is not mentioned in the Quran, but used to explain why they are on earth. According to the Quran, they are on earth and teach humans sorcery. According to the Muslim story, some angels wanted to destroy all humans because they are sinful, but God said, they shouldn't be so harsh to humans. If angels would live on earth, they would also sin. So Harut and Marut made a bet with God, they wouldn't sin if they lived on earth. However, they lose the bet, commit sins, and are not allowed to return to heaven.