demon, vampire

Story of: demon, vampire[Part of the fantasy + sister control + no CP + no harem + restrained vampire, no male cohesion, no female competition; the sister control part is not ambiguous, please feel free to eat it] "Where were you when I was killed by the vampire you said? Where were you when you were supposed to stop the vampires from doing evil! Are you here to kill me who was still a human just a few days ago?!" He stared into the eyes of the demon slayer with strong murderous intent.... A 17-year-old human boy was attacked and killed by a vampire. The "inverted cross" he had worn in his left ear for many years took effect, causing him to mutate into the Six-Winged Demon King; for a long time, he yearned to die completely.But before he died, he wanted to eliminate all the vampires who were causing chaos in the world.