In this world, humans coexist with blood-sucking tribes that survive by feeding on them. Those with intelligence and reason are called "Vampires," while those who lack both are known as "Feral Vampires."

Vampires have integrated into human society, living alongside mates and partners. Their existence is socially accepted, and persecution is a punishable offense. On the other hand, Feral Vampires are recognized as threats to both humans and Vampires and are subject to extermination. Those capable of hunting them are called "Vampire Hunters." It is said that only silver bullets and stakes are effective against Feral Vampires, and only a select few humans can wield them. Feral Vampires are mostly active at night, indiscriminately attacking any human they encounter.