メイジー

Maisie is a mischievous fairy which April sealed away in a book. Despite being pint-sized, she’s not your typical fairy, with a personality just as treacherous, caustic, and brutal as April’s. Maisie is also capable of becoming human-sized (albeit as a loli), which helps during the training scenes...

Seeking retribution for her years of incarceration at April’s hands, Maisie offers a Denis a deal: ”Remove this seal, and I’ll grant you the power to revenge yourself against April.”

MangaGamer