Gyakusatsu Mahou Shoujo Belial☆Strawberry

Synopsis

It's been ten years since the demons have taken over Earth. Since then, humans have been treated like trash. A righteous faerie, who cannot stand seeing humans being trodden upon, came to Earth from Heaven. She is searching for a kind-hearted person to help her fight the demons, because faeries cannot attack demons directly due to a pact from the ancient times. (Source: MangaUpdates)