My Mistress's Breasts Make Me OP!

Genre: Ecchi/Battle ShounenWhen you’re at death’s door, nothing becomes more precious than your own life, and you’ll do anything to keep it… even become the slave of the vampire princess!This is the fate of young Lyon, torn from the grasp of death by Ayra Volkom—princess of the vampire kingdom of Mildelar—but at a steep price.To become her familiar and fight for her amusement against the familiars of other vampire nobles.But Lyon has something that makes him different from the other familiars.His strength… is unleashed when he thinks about his mistress’s boobs!