Douluo: Ancestral Dragon Legend

A young Earthling named Ao Tian transmigrates to a primitive planet and becomes a young dragon. The long life of a dragon leaves him extremely lonely, and in the end he chooses to fall into slumber.

Five hundred million years later, Ao Tian wakes up and discovers that the planet has been ruled by humans, and that one of its continents is called Douluo Continent.

The Spirit Hall, the Haotian Sect, Bi Bi Dong, Tang San... Ao Tian's memories sealed for billions of years finally open, and he at last finds something interesting.

"Little Nana, don't call me forefather. Call me Brother Tian."

Gu Yuena blushes. "Okay, Brother Tian."

He hears that the strongest being in the divine realm, the Dragon God, who secretly absorbed a sliver of dragon qi leaked from his slumber and transformed into a dragon, has been hacked apart in the divine realm.

The divine realm, the divine kings? He can swat them into pieces with one claw!

Invincible story.