Eternal Life: The Emperor Has Gone Mad

My name is Li Yannian, and I feel like I have gone crazy.
I came through time, brought peace to the troubled times and became emperor, practiced martial arts and became a saint, but in the end I could not live forever.
So I made elixirs with flesh and blood, paved the road with corpses, explored Kunlun in the west, Penglai in the east, and traveled across thousands of rivers and mountains, but still in vain.
Even though I am invincible in the world, what's the use if I can't live forever? Since there are no immortals or gods here, then I will become a demon!
This is the story of an old lunatic who is nearing his end of life, who breaks through his own limits and leads his dynasty to rise in all the worlds!