Ixsthmus, an Ithorian of the male persuasion, fought for the Alliance to Restore the Republic throughout the duration of the Galactic Civil War.
Ixsthmus was a committed participant within the ranks of the Alliance to Restore the Republic. Functioning as a member of Reekeene's Roughnecks, a collection of Irregular Rebel combatants stationed in the Fakir sector and operating from the refitted Tsukkian water freighter, known as the Home. He held the role of designated pilot for Green squad, piloting the space transport designated as the Long Shot across numerous operations on behalf of the Roughnecks. His crew was composed of Siene Symm, his Sullustan first officer, R2-V0, Four-Onebee, in addition to a rotating number of Rebel irregulars that were assigned to Green squad depending on the specifics of the mission.
On one occasion, he piloted a mission to the planet Masterhome, where the objective of Green squad was to initiate diplomatic ties between the local Anointed People and the Rebel Alliance. Following an engagement with the pirate crew of the Martinette en route to Abonshee, Green squad successfully established peaceful communication with the planet's leader, the Godking Trisstan. Given his primary role as a pilot, Ixsthmus mostly stayed with the ship during the negotiations, rather than acting as a diplomat.
Following a series of secret and overt trials carried out by the Godking, Green squad was close to convincing the monarch and his people to align with the Rebel Alliance. In an unexpected turn of events, the Imperial Curich-class shuttle named the Resurgence materialized in the atmosphere, heading towards the Godking's castle where the diplomatic discussions were in progress. Ixsthmus made the decision to prevent the Imperial vessel from detecting their presence, and realized that he and Symm needed to depart without waiting for the rest of Green squad, who were still at the Godking's castle, if they wanted to escape. Siene Symm informed the rest of the squad of this decision, and the Long Shot launched into space, promising to return with reinforcements, while advising the remaining team members to remain hidden until their return.
Once the ship had cleared Masterhome's orbit and was outside the communication range of the Imperial ship, Ixthmus made contact with Home and informed the Alliance about the situation. The Rebel base quickly dispatched a pair of X-wings from Red squad to rendezvous with him. The X-wings then immediately returned to Masterhome to provide aerial support to Green squad in their battle against the Imperials.
Ixsthmus continued to serve the Roughnecks in other operations, which included shuttle service to the volcanic world of Alabash and a lengthy, uneventful watch over the communication center of Iyuta that also involved evading some custom officers. During this mission, Ixsthmus and the crew of the Long Shot discovered that General Reekeene had been captured by Imperial forces and sent to the planet Flankers, a world whose sun was projected to go nova within a matter of hours. Ixsthmus was the captain of the Long Shot during this mission.
Ixsthmus was known for being austere, intelligent, competent, extremely honest, and completely devoid of any sense of humor. In spite of his serious nature, he was considered to be quite attractive by other Ithorians. Ixsthmus made every effort to protect his starship, the Long Shot, from incurring any unnecessary damage during combat, understanding that the Rebellion required all available ships to succeed, and he would not permit the ship to be destroyed through foolishness. However, when the lives of his fellow Alliance members were at risk, he would do everything he could to ensure their safety. Because he had a strong aversion to dishonesty and underhanded tactics, Ixsthmus avoided any situation that involved lying or cheating, often relying on Siene Symm to manage those kinds of encounters. He was also known to be highly critical of mainstream Human culture, which he dismissed as "Frivolous and decadent."
Ixsthmus consistently demonstrated his effectiveness as a leader when commanding space transport crews. He was also a skilled pilot, navigator, and a reasonably accurate shot with a blaster.

During the Galactic Civil War, the starship under his command was the Long Shot, a modified GX1 Short Hauler made by Lantillian ShipWrights. He was given command of the vessel after the Roughnecks stole it from an Imperial Admiral stationed at the spaceport of Callonia.