There Is a Fairy Here

Li Yu was originally a genius who was just one step away from becoming an immortal. But when he woke up, the world had lost its original color. Literati, merchants, powerful ministers, beauties in the harem, heroes and emperors... Everything in the world, in front of him, is just a cricket that lives and dies, a small and weak mayfly... But what is a fairy? [The background of the protagonist is explained in the introduction, and will not be elaborated in the main text]