I, Rat Rat, Have Swallowed a Corner of Heaven

The protagonist Lin Xiaobei travels through time and becomes a treasure-eating rat at the bottom of the world of cultivation. He awakens the [Bao-eating Evolution System] and evolves by swallowing everything. From a mouse being chased by a cat demon, he became the lord of all realms. However, when he stood at the top, he discovered that his rat body was actually the reincarnation of the ancient Sky-Eating Rat, and the so-called "system" was just a back-up left for him before his death in his previous life...