Their fights among themselves destroyed the land, split the seas, ripped apart the skies, and shattered the canopy housing the world’s Celestial Foundation.

The canopy separated the world from the infinite space known as the “Sea.” With that canopy gone, the rest of the world easily collapsed. The world was frail and couldn’t bear the harsh environment of the Sea.

And so Taylor was thrown out into it. Either the other reincarnated people had killed each other off or they had been unable to survive the Sea themselves, as Taylor couldn’t find any of them. Everything that made up his world was reduced to dust, and as the only one from it who could survive in the Sea, he found himself floating alone.

...

Though he had no desire to fight or interact with anyone, Taylor was naturally drawn into the struggle, and his rank began to rise.

...

As he grew accustomed to the ways of the monsters, he became more honest in his appetites, and before long he was at the top of the hierarchy. In short, he became the Demon Lord.

After that, he decided to follow his heart. First, he renamed himself Demon Lord Gorbagion. It seemed like a fittingly grim name for one of his station.

-Volume 13 Chapter 9