In the true dragon's nest, Qin Mu finally achieved what he wanted and comprehended all of the dragon language inside it.
Elder Qing Huang was a divine dragon so he knew all of the dragon language. His abilities were extremely high, to the point that Qin Mu didn't know what realm he was exactly.
However, to be able to become the master of Green Dragon Palace, one of the four great celestial palaces of Founding Emperor Celestial Heavens, he should have been stronger than Saint Woodcutter or King Yama.
The combination of the stars was known as the celestial heavens, but separately they were known as the five palaces. Green Dragon Celestial Palace ruled the sixty stars of Eastern Heaven, White Tiger Celestial Palace ruled the twenty-seven stars of Western Heaven, Vermillion Bird Celestial Palace ruled the thirty-nine stars of Southern Heaven, and Black Tortoise Celestial Heaven ruled the Northern Heaven.