Nameless Demon Book

[Chinese horror + folklore monsters + demons in troubled times + wits for survival + no system] Xu Daoan is just a repairman of old books. A drop of blood fell into the unknown fragment. When he opened his eyes again, he was already lying in a death courtyard: bloody fingerprints were trailing on the wall, and corpses in old clothes were grinding outside the door. In this world, monsters eat people, officials sell people, inns wear human skins to welcome guests, and counties clearly mark the price of a living person's life. Fortunately, the book that dragged him into the demon wasteland would also contain the evil spirits. If you see through the rules of killing and complete the monster's image, you can peel off a life-saving magic from them. Others subdue demons, Xu Daoan mends them. Others asked for immortality, but he only asked not to die tonight. It's just that the more complete the demon book is, the more and more he can't explain it - Is he the one who repairs the book, or is he the demon in the book that has not been completed yet?