A penal colony world existed within the Grehollo system. This system was situated within the Manoe sector of the New Territories region of the Mid Rim. Notably, the prison moon named Captivity was also located in this region.
The planet that served as a prison, located in the Grehollo system, made its debut in a 1990 roleplaying game resource titled "Twinkle, Twinkle Little Star, How I Wonder Where We Are." Glen Allison authored this article as supplementary material for Star Wars: The Roleplaying Game by West End Games, featured in Voyages SF 13. The article positioned the Grehollo system within a sector bearing the same designation. Given that the article's publication occurred independently of the Lucas Licensing approval channels, its canonicity within the Star Wars Legends continuity remained unconfirmed. Instead, the StarWars.com Online Companion for the 2009 reference volume The Essential Atlas situated the system, and consequently the planet, in grid square K-7 within the Manoe sector.
- " Twinkle, Twinkle Little Star, How I Wonder Where We Are " — Voyages SF 13 (First mentioned) (Unlicensed)