MTL - From the Dungeon, Slaughter the Demon Apostle - Chapter 591 several possibilities

The Grand Sovereign, Kang Chul-In. The man who was so strong that he had to be defeated. Having lost, he must now go back in time to take up the challenge of becoming supreme in the Continent of Pangaea. Will Kang Chul-In be able to overcome the 9 other Grand Sovereigns in order to grasp the Continent of Pangaea within his hands?

A recurring nightmare afflicted Khan's nights since the Second Impact. His dreams replayed the scenes of the crash of the Nak's spaceship, an alien race that the humans had defeated five hundred years ago.

I exist in the darkness, disappear under the bright light, and will eventually devour the sun and turn into the shadow of all things… Known by people as the indescribable terror of darkness; the king of shadows; the dark day; the existence of the shadow of the world , is still just a somewhat special high school student, facing a weird death game…

- Description from novelbuddy

The head of the London Association of Mages, the most powerful Saint Archmage in the world, Audrey Davis, accidentally transmigrated to another world due to a magic accident. She was an 18-year-old human girl.