The Guardian of the Dead

The world is divided into zombies, humans, and creatures somewhere in between. The spread of a virus known as "wind death disease," which turns living things into zombies, has completely changed the world. Are those infected zombies or humans...? While the treatment of zombies remains uncertain, Togo, who works as a conservation officer collecting and containing zombies, meets a strange boy who is neither zombie nor human. He is the only case of recovery from the disease, which is supposed to be fatal once a zombie is turned. Are zombies people? Or corpses?

(Source: Kadokawa, translated)