Rimbor is one of many human colonized planets that exist by the 30th century. It is a member of the United Planets and is renown for being a violent, impoverished world. Gang violence is commonplace and keeps the Science Police and government of Rimbor busy and largely prevents them from making more headway in cleaning up the world. One of if not its most famous denizens is Jo Nah, the Legionnaire called Ultra Boy. He was formerly a member of the Emerald Dragons, one of the most prominent gangs on Rimbor.
In the postboot continuity, it was established that Rimborians had different organ placement inside their body than Earthlings despite their heritage. The Legionnaire Timber Wolf was also from Rimbor in addition to Ultra Boy.
In other media
Young Justice: Invasion
In Young Justice, the Light used six members of the controlled Justice league to go on a sixteen hour rampage on this planet, for reasons yet unknown. This event caused several alien races to take interest in the Earth, making up a majority of the second season's plot.