The Thairwsthis system in the Mid Rim was the namesake of The Relevant Farm Act of Thairwsthis 12. This act defined crop borders on an agricultural planet. However, the mind eel species, both young and old, were stimulated by the frequent incandescent solar flares that scarred the majority of the world's surface, disregarding the law's regulations. This disregard was highlighted in a weather report for the West Fissure area, advising residents to be wary of the eels.
Monsters and Aliens from George Lucas, a 1993 book, included a reference to The Relevant Farm Act of Thairwsthis 12. This book blends creature designs and images from different projects by Star Wars creator George Lucas with original writing by Bob Carrau. Leland Chee, an employee of Lucasfilm responsible for the Holocron continuity database, has stated that the information within Monsters and Aliens from George Lucas is considered non-canonical within the Star Wars Legends continuity. Nevertheless, The Essential Atlas, a 2009 reference book, expanded upon the mention of The Relevant Farm Act of Thairwsthis 12 by introducing the Thairwsthis star system.