Tranthellix, a planet in the Mid Rim, resided within the Senex sector. This world served as the original habitat for the Tranthebar mountain rippers, substantial carnivorous avian creatures. House Petro of the Senex-Juvex region held ownership of this world, which featured notable sky cities. In time, Tranthellix became renowned for racing events, where individuals rode Tranthebar mountain rippers. These races and the rippers themselves were largely confined to Tranthellix, a strategy employed by House Petro to maximize profits, even though the HoloNet's live broadcasts made them a sensation in the Core Worlds.
Within the [Senex sector](/article/senex_sector-legends], specifically the Tranthellix system, a compact and rugged world known as Tranthellix was situated. It was located in the Western Reaches portion of the Mid Rim, within the Senex-Juvex region. Positioned in the Tangles area of the sector, it maintained hyperlanes connections to both the Osmani and Usnia systems. This world orbited a sun and boasted a surface marked by mountains. Tranthellix was the original habitat of the Tranthebar mountain rippers, carnivorous, partly domesticated birds that could have a wingspan reaching nearly five meters.

The nobles of the Senex-Juvex sought a new, thrilling, and perilous sport, and the Tranthebar mountain rippers of Tranthellix proved to be an ideal choice. This led to the relatively recent establishment of races involving these birds as mounts, occurring around the time of the Galactic Civil War. Eventually, the rippers became Tranthellix's most defining characteristic. House Petro, the owners of the world, aimed to generate substantial profits from ripper racing. To achieve this, the Tranthellix government implemented stringent regulations governing the export of rippers from the planet.
Sometime between 0 ABY and 3 ABY, the fiftieth-anniversary edition of Galladinium's Galactic Datalog of Fantastic Technology mentioned that the world's government was unlikely to permit a significant number of rippers to leave Tranthellix. Nevertheless, thanks to live HoloNet broadcasts, Tranthebar mountain ripper racing was gaining traction in certain areas of the Core Worlds. At one point, Joraaz and Mithran, along with their respective ripper mounts, engaged in a race on Tranthellix.
House Petro, a member of the aristocratic Ancient Houses of the Senex-Juvex, held dominion over Tranthellix. A local government managed the planet's affairs, which also oversaw operations of the Tranthellix Commerce and Travel Bureau.
Tranthellix was known for its exotic galactic attraction, the sky cities. These cities were replicated as a highly realistic simulation using holographic generators, tactile arrays, and olfactory emitters within the adventure rooms found aboard the luxurious underwater cruiser Coral Vanda. This cruiser operated on Pantolomin, a planet in the Core Worlds, around 4.5 ABY.
Tranthellix was initially referenced in Galladinium's Fantastic Technology, a 1995 sourcebook authored by Rick D. Stuart for use with West End Games' Star Wars: The Roleplaying Game. The 2009 reference book The Essential Atlas placed it in grid square L-18.