Vampire Dragon Slayer Magic

Blood Dragon Slayer Magic (血液の滅竜魔法, Ketsueki no Metsuryū Mahō): otherwise known as Vampire Slayer Magic (悪霊の滅竜魔法, Akuryō no Metsuryū Mahō) is a Caster Magic, Lost Magic and type of Dragon Slayer Magi that allows Dressia to take the blood she drinks from others, as well as her own blood, and turn it into magical energy much akin to that of a Blood Dragon's, in order to use for offensive and defensive spells. The vampiress Dressia, is one of its known user.