Battleworld
Battleword was in uninhabited planet in the Andromeda galaxy used by the Beyonder to stage the contest between their Chosen Heroes.
It was presumably chosen due to it's remote location, thousands of light years from Earth it's breathable (to humans) atmosphere, and the fact that it is located in a star system which has been uninhabited and unmonitored since the fall of Skrullos during the Kree-Skrull War.
Since the defeat of the Beyonder, and the return of the Chosen Heroes to Earth, it is once again uninhabited.
Due it its lack of natural resources, little is known about the planet and its history, and what little was one recorded is believed to have been lost when the archives of the Skrull Empire were destroyed during the war.
Nathan Garrett is buried on the planet.
Geography
The surface of the planet is barren red rock and sand. The number of mountains and large rock formations suggest it was once seismically and volcanically active, but this has not been the case for at least several hundred years, likely for older.
Its atmosphere is low in oxygen compared to Earth, but is safe for Humans to breathe.