For hundreds of years, vampires have existed in the shadows of human society. Possessing physical abilities and regenerative powers far superior to humans, they have lived hidden throughout the world, sustained by their long lifespans and resilient vitality. While most blend into human society and live quietly, some vampires treat humans as prey or revel in slaughter, becoming the cause of numerous disappearances and serial killings. Over time, the existence of vampires became a fact known only to a few government agencies and secret organizations, leading to the creation of a specialized organization called the Hunters to eliminate them.

Hunters thoroughly study vampire weaknesses and apply them in the field. Specialized equipment for dealing with vampires—such as silver bullets, silver-plated swords, holy water rounds, UV projection devices, and weapons that have undergone blessing rituals—is constantly being developed. Every Hunter is deployed to the field only after being educated on vampire ecology and weaknesses. To them, vampires are not subjects for coexistence, but threats that must be eradicated.