Qat Chrystac, a world characterized by its instability, radioactivity, and volcanic nature, became a contested territory for more than a decade between the Rebel forces (later evolving into the New Republic) and the Imperial military.
Molten rock dominated the planet's landscape, punctuated by sizable mesas formed from volcanic glass that rose from the volatile, waterless expanse. The numerous fissures and crevasses across the surface emitted radioactive lava, which disrupted computer systems and sensors. Due to the intensely high temperatures and the poisonous Type IV atmosphere, protective environmental suits were absolutely essential for survival. The planet's gravitational pull measured 1.4 times the standard. A single day lasted twelve standard hours, while a year consisted of 166 local days.
A hidden outpost was established when a Rebel cell, composed of some of the Alliance's most skilled combatants, concealed a heavily fortified and shielded vessel deep within the planet's rocky terrain. The Imperial forces responded with a counterattack, but the resolute Rebel fighters repelled it.
As the Thrawn crisis unfolded, the conflict on Qat Chrystac persisted. Elite radtroopers continued to comb the planet's surface in search of the concealed base, while the New Republic supplied the base to maintain pressure on one of the few remaining elite Imperial units following the Emperor's downfall. By this juncture, the New Republic had approximately two thousand personnel stationed on the planet, while an Imperial siege platform in orbit was manned by 1,500 Imperial soldiers.
General Garm Bel Iblis and his contingent were fighting on Qat Chrystac when they picked up Lando Calrissian's distress call originating from Nomad City subsequent to the battle that occurred there. Following Calrissian's evacuation order, all of Nomad City's inhabitants were transported to Iblis's fleet.
Several weeks preceding the Battle of Bilbringi, Wedge Antilles recalled Rogue Squadron's engagement with two squadrons of TIE Fighters during the Empire's latest attempt to seize control of the system. These TIE fighters were piloted by Thrawn's newly developed cloned pilots, which presented even Rogue Squadron's exceptional abilities with a significant challenge.
The video game Star Wars: Rebellion and its companion strategy guide, Star Wars: Rebellion: Prima's Official Strategy Guide, erroneously place Qat Chrystac within the Sumitra sector of the Outer Rim Territories. Furthermore, the in-game description of the planet depicts a surface covered in various types of grasses, some reaching several meters in height, which directly contradicts the planet's radioactive environment as described in other sources.
Star Wars: Rebellion: Prima's Official Strategy Guide contains a misspelling of the planet's name, rendering it as "Qat Chrystal."