Long ago, in an epic battle of might, King Phelios defeated the Vampire King Duzell. And as both lay dying, Duzell swore that his reincarnation would find King Phelios' reincarnation and exact his revenge. ...

Maira is a half-vampire, and sworn enemy of vampires that use humans as lifestock. She's trying to find a way to repay Kyousuke for donating his blood for her to fight her battles.