Heaven-Devouring Rat Sovereign

The protagonist, Lin Xiaobei, transmigrates into the cultivation world as a lowly Treasure-Swallowing Rat and awakens the [Treasure-Swallowing Evolution System]. He can evolve by devouring anything. From a mouse chased by a cat demon, he devours his way to becoming the ruler of all realms. But only when he reaches the pinnacle does he discover that this rat body is actually the reincarnation of the ancient Heaven-Devouring Rat, and the so-called "System" is nothing more than a contingency plan he left for himself before dying in his previous life...