My Dear, Curse-Casting Vampiress, Vol. 1 (manga)

The world is full of vampires. Supernatural creatures who drain the blood from humans without mercy-fighting such beings is the foundation of Isuzu Osaka's life. But humanity is losing the war, and so desperate times call for desperate measures...And so, Isuzu sets out to strike a deal with a powerful vampiress whose beauty drives all who gaze upon her insane in the hopes of protecting his friends...