In the Emperor's Later Years, I Can Travel Both Ways!

Good news: Time traveled! Bad news: I have traveled back in time to an old emperor and his lifespan is approaching. Lu Yan originally thought that there was no solution to this situation, but unexpectedly, a light suddenly bloomed in his mind, and a portal slowly emerged. The world opposite the portal turned out to be the supreme true world: the prehistoric world! ······ This book is also called [The Emperor is in his later years, why is he not dead yet? Thank you for the invitation: I just became the Great Emperor, I have a double doorYou bullied my Great Emperor in his later years and suppressed everything with your backhand