Pokemon Ultimate Champion

The protagonist was bound to the system due to an accident and went to the world of Ultra Emerald. After solving that world, Team Rainbow Rocket defeated all the regional champions and ascended to the throne of the Ultra Champion, but he didn't expect it. He thought he could go home after completing the mission, but he came to the animated world where Xiaozhi was. Unexpectedly, the system would ask him to go on another championship journey, but this time it was different from the one in the ultimate world. He would conquer all regions in a state of complete victory. (The protagonist's strength is that of a champion in his heyday. The first echelon of strength is basically all mythical beasts.)