Kvag Gthull was a Dark Jedi of the Human species, identified as male, who served within Emperor Palpatine's organization known as the Dark Side Elite. Stationed at Bast Castle, the Elite's fortress on the planet of Vjun, his primary duty was extracting information. He interrogated Major Ntthan of the New Republic following Ntthan's capture in 10 ABY, seeking the location of the hidden Solo twins.
Later, acting under the Emperor's directives, he participated in an attempted kidnapping on the planet New Alderaan. Under the command of Executor Xecr Nist, the darksiders infiltrated the world, and Gthull successfully captured the children. However, Rayf Ysanna, a young Jedi, rescued the twins, and Gthull met his end at the hands of their mother, Leia Organa Solo.
Kvag Gthull, a male Human Dark Side Adept, was in the service of Galactic Emperor Palpatine during the Emperor's rebirth through clone bodies. When Palpatine established an elite group of Dark Jedi, called the Dark Side Elite, Gthull was selected as one of the original seven Dark Jedi to join. This group, headed by Executor Sedriss QL, established their base at Bast Castle on the planet of Vjun, where Gthull served as the chief interrogator.
In 10 ABY, Luke Skywalker, a Jedi, once again killed Palpatine in battle. However, Palpatine returned again and sought to capture the Force-sensitive children of Skywalker's sister, Leia Organa Solo, who were hidden on a secret sanctuary planet of the New Republic. After the Empire captured Major Ntthan of the New Republic in an uncharted region of space, he was taken to Bast Castle and placed under Gthull's control. Gthull's assignment was to torture Ntthan to reveal Organa Solo's location.
Gthull employed interrogation droids on Ntthan, who proved remarkably resistant. Despite requiring twelve hours of interrogation, Gthull eventually broke Ntthan's resistance, and Ntthan revealed the name of the planet, New Alderaan, along with its coordinates. Palpatine arrived at Bast Castle to oversee Gthull's success. Palpatine also introduced the new Executor, Xecr Nist, who replaced the recently deceased Sedriss, to command the group. Palpatine ordered Gthull and the other Dark Jedi to travel to New Alderaan on a covert mission to capture Skywalker and the Solo twins, followed by an attack on the settlement using AT-ATs. Gthull piloted an I-7 Howlrunner as part of Dark Side Squadron during the journey to New Alderaan. Upon arriving undetected, Nist sent Elite members Tedryn-Sha and Krdys Mordi to confront Skywalker. Gthull, along with three others, accompanied Nist to abduct the children.
However, Gthull lost contact with Sha and Mordi and sensed their life force disappearing from the Force. He reported this to Nist just as they arrived at the building where the children were located. Nist sent Gthull inside to seize the twins, while he and the other darksiders were confronted by Skywalker's Jedi recruits: Kam Solusar, Rayf Ysanna and Empatojayos Brand. After losing one Dark Jedi and being defeated in combat by Solusar, Nist ordered Gthull to signal the AT-ATs to attack. Emerging from the building with the twins, Gthull signaled the heavy armor. However, Rayf Ysanna used the Force to levitate the twins from Gthull into the arms of Winter, their caretaker. Organa Solo, having just defeated Sha and Mordi in Skywalker's quarters, emerged and shot Gthull with a blaster, killing him. With Gthull dead, Nist and the remaining two darksiders retreated from New Alderaan under the cover of the advancing AT-ATs.
Kvag Gthull, a darksider, demonstrated loyalty to Galactic Emperor Palpatine and was appointed chief interrogator at Bast Castle. In this role, he inflicted painful torture on Major Ntthan to please his Master and uncover the Solo twins' location. Gthull regarded Sha and Mordi as incompetent for failing their mission on New Alderaan and displayed disdain for the Solo twins, referring to them as "Jedi brats." Gthull was an imposing figure, dressed in the traditional attire of the Dark Side Elite: black hooded robes, gauntlets and boots.
Kvag Gthull's initial appearance was in the comic series Dark Empire II 6, where he was killed.
In the Dark Empire II audio drama, Xecr Nist largely replaces Gthull's role. Nist interrogates Ntthan, using scarab droids filled with poison. After Gthull captures the Solo children on New Alderaan, Nist takes custody of them and guards them, while the other darksiders battle the Jedi. With all the Dark Jedi slain, Nist attempts to escape but is shot by Organa Solo. Gary Gerani, in the Star Wars Galaxy Collector article "ComicScan: Comics That Almost Were", suggested that Gthull was originally intended to appear in Veitch's proposed short novel Lightsider, set before Dark Empire II and introducing the Dark Side Elite. However, Lightsider was never published.