Bookworms are creatures that attaches to a certain book, they prey on humans who reads said book by taking their soul. Humans with their souls taken becomes thoughtless and emotionless, an empty vessel. Bookworms have monster or animal features such as claws, sharp teeth, horns, and some even have weapons. The number on their body represents the page number which they're attached to, waiting for the reader to open said page. Once opened, they will jump for the kill. Their page number determines their strength; the higher the number, the weaker they are.