After Signing in the Cold Palace for 800 Days, I Will Become the Best Immortal in the World

[Multiple heroines + sign-in flow] In the Dayu Dynasty, demons danced wildly, and the imperial power was as powerful as the sky. Xie An traveled through time, was stabbed in the back by his relatives at the beginning, and was sent to a cold palace where eight hundred concubines had died. He became a low-level guard who could be swallowed up by the evil energy at any time. Innately, everyone is an ant. Fortunately, he awakened the [Martial Saint Sign-in System]. Sign in at the Cold Palace and get the "Tathagata Palm"! The light of the Buddha shines universally, and all evils retreat! Sign in at the front desk of the palace and get the "Tai Xuan Jing"! The true energy transforms into a dragon, overwhelming everything! Sign in at Tianlao and get the "Six Meridians Divine Sword"! The light of one sword chilled the nineteen states! In order to save his life, Xie An decided to sign in silently in the cold palace and never cause trouble. Until the Dayu Dynasty faced the disaster of annihilation, demon troops came to the city, and the civil and military forces of the dynasty were helpless. Until the enemies came to Leng Palace and the demons came to the city. Xie An slowly drew out his sword and looked sternly: "I'm just a bit of a loser. Do you really think that this uncle is a fool?" That day, he reached the sky in one step and suppressed for eternity! Only then did the world discover with horror that this invincible immortal had been by their side all along!