Versatile Mage: I Became the Ancient King, but the System Arrived Too Late

When Zhao Chen woke from a nap and transmigrated to a world of magic, he thought it was pretty great. Magic sounds wonderful. He had to learn it! But why had he transmigrated into the Ancient King!? Come on, this was the Ancient King who founded the Huaxia Undead Empire! At the pinnacle of forbidden magic across five elements, he had no equal in the entire world! And where was the System!? How was he supposed to play without a cheat! After a full ten years of anxiety and unease, Zhao Chen finally merged with the Ancient King. Just as he was about to leave the Sha Abyss Imperial Mausoleum and return to the colorful human world, the System showed up again!? Seriously? It was a whole ten years late. What kind of joke was this! He had already become the Ancient King, a mighty Undead Emperor standing at the pinnacle of this world! It would be pretty hard to turn back and be a good person now! Unless... First sign-in reward: the Shadow Troops! Every Shadow Warrior is Monarch Level! The nine ghost generals of the legions are all Supreme Monarch Level! And the Shadow King, Tara, is Emperor-level! Bo City is his territory! The Black Vatican's lackeys and those stupid demons who dare to plot against him are practically asking to die! This magical world has been divided for far too long! I, the Ancient King, swept across the Six Kingdoms and ruled the Eight Directions in life! In death, I shall unite the entire world! Everything shall belong to my Great Qin Huaxia! And every beauty shall dwell in My Imperial Majesty's magical Epang Palace!