Zero Judgment by Kota Quinn

Zero is a tracker for the Elite Guard, the supernatural police that hunts down rogues. Zero’s number one goal was to work for the Elite and seek revenge on the vampires who killed his childhood friend.
But after so many years of moving from place to place, he wants to settle down. Zero volunteers to help guard one of the magical small towns where paranormals and humans live together openly.
He’s settled in this new town, has a life, friends, and hopefully, soon he’ll meet his mate. But what he doesn’t expect to find is his childhood friend alive and well. Except his friend isn’t alive. He’s undead, just like all the creatures he’s hunted down.