Gaba Kawa 

Demons like Rara are supposed to cause mischief in the mortal world and draw humans to darkness. They're not supposed to help mortals and they're definitely not supposed to fall in love with them! But that's just what happens when Rara enters high school, where a hot guy named Retsu Aku calls her "Gaba Kawa"! While demons gain power by causing mischief, the opposite is also true--if Rara uses any of her powers to help mortals, she'll immediately lose that very power. If she loses enough power, she'll disappear! Poor Rara. What's a "Gaba Kawa" demon to do?