Seraph of the End: Vampire Reign

After an unknown virus wiped out all adults on earth, vampires appeared and ruled over the surviving children, treating them like livestock. Yuichiro Hyakuya survived along with other orphans by giving their blood to vampires, until Yuichiro escaped four years ago. Now he is a member of the Moon Demon Company, a unit in the Japanese army dedicated to hunting down the vampires he blames for the death of his family.