Shai Domain represented a Domain within the Yuuzhan Vong Warrior caste. The individuals belonging to this domain were recognized for their dedication to and pleasure derived from pain, a trait that was considered extreme even among the Yuuzhan Vong. Mongei Shai, a prominent figure from Shai Domain, participated in the Yuuzhan Vong scouting party that infiltrated the galaxy. His death during the scouting mission on the planet Bimmiel was a point of honor for the Domain.
Shedao Shai, Mongei Shai's grandson and a Commander, is another significant member; he spearheaded the Yuuzhan Vong's attack targeting Ithor. Following Shedao's demise and defeat, Shai Domain faced disgrace. Despite this, a Yuuzhan Vong who had trained under Shai Domain was dispatched as an assassin with the objective of eliminating Elan after her presumed betrayal.
The initial introduction of Domain Shai occurred in the 2000 book The New Jedi Order: Dark Tide I: Onslaught, penned by Michael A. Stackpole.
According to Shelly Shapiro, a Del Rey Editor at Large, as mentioned in the Star Wars: New Jedi Order Round-Robin Interview, the idea of the Yuuzhan Vong's affinity for pain was first specific to Domain Shai. However, subsequent writers misinterpreted this and generalized it to the entire Yuuzhan Vong species.