C5448 Answer

The Heaven Earth Spirit Flame of the Heavenly Fire Palace was left behind by the Great Cheng in the Heavenly Fire Palace. There was a saying that if someone advanced to the Great Cheng, they could go to the Heavenly Fire Palace and try to subdue the Nether Thunder Heavenly Fire.

Kou Yuxin, an Advancement Mahayana did not take long. He only had less than two hundred thousand years