After Successfully Assassinating Qin, I Have to Survive in the Forbidden Land for a Thousand Years.

He traveled through time and became Qin Wuyang. In order to survive, he helped Jing Ke succeed in assassinating Qin. He escaped into the eternal forbidden land. After a thousand years, the seal was finally broken. Although he was invincible, he upheld the supremacy of Gou Dao! The truth about the existence of the monster clan, the distorted history and legends, and the source of the huge fear in the dark. In order to cope with the coming catastrophe, the protagonist takes the identity of Qin Wuyang and is active in various human countries, leaving behind legends; at the same time, he transforms into a demon emperor and forms a demon kingdom, just to counter the prophesied catastrophe that is coming to Kyushu!