This is NOT official and just a fan idea, please do NOT take this seriously.
NPCs in this story = Humans in ours, just to clarify.
The Creation:
Long ago, the universe was created. We, as NPCs, do not know what created this. Some theorize a large bang, some theorize higher powers. What we know however, is we are on our land, our World.
The Split:
Our world is split into 5 separate lands, The Overworld, our forests, tundras, deserts, jungles, oceans. The Underworld, the complete opposite to the Overworld, it is a barren, humid landscape, full of Demons, and other weird creatures. The Crimson, or more commonly known as "The Underworlds Daughter". Because it comes from the Underworld. It is full of strange creatures, even stranger than the Underworld! The Corruption, the "Underworlds Son". It is more purple compared to the red crimson. Likely how they got their names. And, it to, has strange creatures... The Hallow, formed by a great Deity, who has now been sealed away in the King of the Underworld. It was a land of the fantasies and dreams.
The Beginning:
It all started when a higher power named Cthulu invaded our towns, cities, settlements, his great, destructive powers (way stronger than the ones we know he has today) demolished our settlements. And we were forced to surrender to him and his armies. He ruled with terror, The Hallow seemed to be able to fend him of, and he wasn't interested in the Underworld. Cthulu destroyed any villages and or cities he wanted. One time he even thought about destroying our race entirely. However, he had grown far to weak to do so, as he had ages over the millenniums of his reign. Thus, the people revolted, and eventually defeated Cthulu, he was sealed on what we thought was the unreachable Moon. He lost many parts of his body, his Liver, his Eyes, his Brain.
The Moon Lord:
Cthulu, or more commonly known as The Moonlord, (because he was trapped on the Moon) was unable to leave. And he had very limited resources and space. He created 4 beings, each made out of their unique impacts.
The Solar Pillar. Created from the harshest of the Sun's Rays. Had the power of the day-night cycle.
The Stardust Pillar. Created from the largest, fastest comets. Had the power over nearby celestial objects.
The Nebula Pillar. Created from the farthest, strongest Nebulas. Had the power over even the furthest stars.
The Vortex Pillar. Created from the strangest wormholes and vortexes. Had the power over the mind, and parts of the Universe itself!
The 1st Rift:
The First Rift marks the beginning of the Under Revolution. The Crimson and Corruption, both fighting for independance. Eventually, the King was overthrown, and was replaced by the Moonlord's Flesh. The Crimson and Corruption both became Surface Biomes. Spreading like weeds, both swiftly gained rulers. The Moonlord's Brain for the Crimson, and its Liver for the Corruption.
The Brain of Cthulu
The Eater of Worlds