Slayer vs Killer

When you're brought up in a society of the dead, the night dwellers, the hunters of the moon, and the hell children, you learn to defend yourself till the last breath. Zeref, a young boy who has grown up in this world, has been trained as a Slayer to kill these species that inhabit the Earth, taking on hit assignments from the Assassination Program for Humans. When his house is overrun one day by the dead and he encounters the reputable vampire Renia, the hunt begins to figure out what she wants to do with the boy.