The long and short of what I have so far, is that an incredibly powerful cosmic agency. Whether a group or individual is not disclosed, summons every great warrior throughout time and space. 

Living or dead, born or unborn. 

To a world that is similar to Battleworld from Marvel's Secret Wars. 

These warriors number in the millions, and created a society on this planet that is constantly changing and growing. New continents rise and fall, though some stay eternal. 

A patchwork world where warriors live, thrive, die, and are reborn countless times. Grudges are held and given up, revenge and forgiveness. 

It's a world created by powerful beings for powerful beings, to give them a place where they belong. Rather than among the lesser beings of the Multiverse. 

[img]http://i.annihil.us/u/prod/marvel/html_blocks_assets/secretwars/i/map/map-ie.jpg[/img]

The world would kind of look like this, except it would always be growing. I'd have to explain how the gravity doesn't change, but I've got a few ideas.

It's definitely a work in progress, but I've got ten or twelve hours left before I sleep.