Zasm Katth was a Human male Dark Jedi who had aligned himself with the dark side. He was a member of the Dark Side Elite, a group of darksiders under the command of the reborn Galactic Emperor Palpatine. In 10 ABY, Katth collaborated with Baddon Fass, another member of the Elite, in an effort to locate the Millennium Falcon on the moon of Nar Shaddaa. He oversaw this operation from the Imperial Star Destroyer known as the Invincible. Leading a group of Imperial stormtroopers, the pair attempted, without success, to enlist the aid of the renowned bounty hunter Boba Fett in their search. They eventually located the Falcon inside Shug Ninx's hangar, but it was devoid of its crew. When Solo returned to claim his ship and tried to leave the planet, Katth ordered the activation of the Invincible's tractor beam. Unfortunately, the beam latched onto the massive Traffic Control tower, causing it to crash into the Star Destroyer, resulting in its destruction and Katth's death.
Zasm Katth was a Human male Dark Side Adept who loyally served Galactic Emperor Palpatine. After his death at the Battle of Endor, the Emperor returned in a clone body and established the Dark Side Elite, an exclusive group of seven Dark Jedi. The Emperor himself empowered these Jedi with the dark side of the Force. Palpatine considered Katth to be one of his strongest darksiders, and therefore made him a member of this elite group. During a confrontation near the New Republic's Pinnacle Base in 10 ABY, Palpatine met his end once again during a battle with the Jedi Luke Skywalker and his sister Leia Organa Solo.
Executor Sedriss QL, the leader of the Dark Side Elite, assumed temporary control of Palpatine's Dark Empire while awaiting the Emperor's return in another clone body. He dispatched Katth and another Dark Jedi, Baddon Fass, to the moon of Nar Shaddaa on a mission. They were given command of the Imperial Star Destroyer Invincible as well as a legion of Imperial stormtroopers, and were tasked with several objectives. Their first task was to contact the bounty hunter Boba Fett and persuade him to assist in the search for the Millennium Falcon, the starship of Han Solo, Organa Solo's husband. They were also required to report any sightings of the Falcon directly to Sedriss. Finally, the Dark Jedi were instructed to eliminate Vima-Da-Boda, an ancient Jedi who had sought refuge on the smuggler's moon.
While positioned aboard the Invincible in orbit around Nar Shaddaa, the Dark Jedi soon observed the arrival of the Falcon. Katth and Fass attempted to secure the ship using the tractor beam, but Solo's exceptional piloting skills allowed him to evade capture and land in the abandoned Duros Sector. Realizing that they would be unable to locate Solo on their own within the labyrinthine passages of that area, Katth and Fass decided to seek Fett's assistance after all. They confronted Fett, demanding his services without payment, threatening to expose his secrets and using the dark side against him. However, Fett retaliated by unleashing his arsenal of rockets, eliminating the stormtroopers accompanying Katth and Fass and escaping in Slave I. This setback was only temporary, as Dark trooper team two reported that they had located the Millennium Falcon inside Shug Ninx's repair shop.
As Katth and Fass made their way to Ninx's hangar, they sensed the presence of Vima-Da-Boda nearby. Disregarding the safety of the local population, Fass ordered the dark trooper Grath to open fire on the crowd with his turbocannon. However, the Jedi managed to escape unharmed. Additionally, Dark Trooper Team Two was eliminated by Solo and his allies, who had left the Falcon to search for Vima. Katth and Fass took the bodies of the fallen stormtroopers and stationed guards aboard the Falcon before returning to the Invincible. The Solos successfully rescued Vima and reclaimed the Falcon, however. After avoiding an encounter with Fett, they attempted to flee Nar Shaddaa.
However, Solo's rival Mako Spince, who was in charge of the Nar Shaddaa Traffic Control spire, detected the Falcon as it passed by and contacted the darksiders aboard the Star Destroyer. Upon receiving this information, Katth ordered the activation of the tractor beam in an attempt to capture the elusive ship. However, Solo attempted to use the Traffic Control tower as cover. Determined to capture Solo at any cost, Katth disregarded all safety protocols and ordered the tractor beam to be set to full power. Solo, however, maneuvered the ship behind the spire, breaking the tractor lock. Katth ordered Fass to reengage the beam. However, as it had been set to full power, the beam began to tear through the massive structure and pull it towards the Star Destroyer. Realizing the danger, Katth desperately ordered Fass to disengage the beam.
However, the order was issued too late. The spire pierced through the engineering compartment of the Star Destroyer, killing the engineers and disabling the main thrusters. Fass contacted the crew of the ravaged deck, demanding that they stabilize the ship, but they were unable to do so. Consequently, the Star Destroyer plummeted to the surface of the moon, killing the entire crew, including Katth and Fass. Emperor Palpatine, who had returned in another clone body, was disappointed by the loss of two of his best Dark Jedi and reprimanded Sedriss for failing to prevent their deaths. Katth and Fass were eventually replaced in the Dark Side Elite by two other darksiders.
Palpatine considered Katth, a seasoned Dark Jedi, to be one of his most valuable servants. As a darksider, his eyes glowed with a yellow hue. He wore clothing similar to that of other Dark Side Elite members, consisting of dark robes, heavy boots and gauntlets, and a hood that concealed his head. Katth was in command of the mission on Nar Shaddaa, holding more authority than Fass. In his eagerness to capture Solo, which he believed would lead to his promotion, he disregarded safety protocols regarding the use of the tractor beam, ultimately leading to the destruction of the Invincible.