According to the clues you provided, I guess this novel may be Swallowing the Starry Sky. This is a fantasy novel. The protagonist is Li Batian, a hero who has traveled to another world. He became a little uncle named "Xie Xun" and later discovered that he had great abilities. He experienced all kinds of challenges and adventures in this world and gradually revealed some secrets.

In the finale of the novel, Li Batian, the protagonist, waged a life-and-death struggle with an alien creature from outside the universe, and finally ended in a draw. Then, the protagonist unsealed his ability and finally defeated this alien creature. The ending of this story is quite wonderful and left a deep impression on people.