Monster, Where Are You Escaping?

Monsters from the Great Yong Dynasty are hidden in the world. Gu Changan, a policeman from the border town, awakens the "Ten Thousand Demons Illustrated Book" and can see through disguises, trace cause and effect, and hunt demons and seize powers. When he leads a group of monsters feared by the world to chase down the world's demons, he discovers that the last demon recorded in the illustrated book is actually himself.