Their rule was killing for blood. At least it used to be when the great King ruled the Vampire Kingdom but he didn't know what dark beasts the future was hiding from him eagerly awaiting for their release. The more swords he dug in the Humans' bodies, the more wildly and quickly the monster awakens inside of them and it was time for the Vampires to pay the price. They didn't know the price would be quite painful because the merciless, beastly monster was ready to take its revenge.