Warworld

Overview
Warworld is a planet-size domain of Mongul. It's capable of intertellar travel.

During Reach's invasion of Earth the Light goaded Mongul into assaulting Earth to force the Reach's hidden fleet.

Trivia

 * Roughly a third of the Daxamite survivors found a refuge on Warworld in exchange for forsaking their religion and pledging themselves in the service of Mongul.