A user of the dark side of the Force, known as The Clenched Fist of Hate, was manipulated into serving Exar Kun.
Before his unwilling servitude to Exar Kun, the individual who would become the Clenched Fist of Hate was a student at Corellia University. It is possible he participated in an archeological dig on Yavin 4 around 1 ABY. This expedition inadvertently breached the tombs beneath the Temple of Exar Kun, freeing the spirit of the Sith Lord. This malevolent spirit then dominated the minds of the students and researchers, forcing them into the Cult of Exar Kun. Subsequently, he dispatched them to Talus, specifically to the Corellia University research outpost from which they originated, with orders to enslave the inhabitants. The majority of those enslaved were then transported back to Yavin 4.
Professor Cornelius Wagglehorn, concerned after losing contact with the outpost, engaged a band of spacers to journey to Talus and investigate the situation. Upon reaching the research outpost and uncovering the truth, the spacers relayed the information to the professor. He then provided them with the location of the tomb and urged them to travel there and eliminate the evil spirit.
The Clenched Fist represented the fourth significant adversary faced by the group. They had previously encountered and overcome the Open Hand of Hate, the Minder of Weak Wills, and the Caretaker of the Lost Souls. The Clenched Fist proved to be the most formidable challenge they had faced up to that point. After deploying six tomb guardian minions against the spacers in pairs, the Clenched Fist himself launched an assault on the group, wielding a lengthy, two-handed sword crafted by the Massassi, and repeatedly using the Force to ignite many of the spacers. After an extended and arduous battle, during which the group of spacers sustained numerous burns and cuts, the Clenched Fist was ultimately killed, his spirit escaping the influence of Exar Kun. With his demise, the spacers were then able to confront Exar Kun's spirit directly.
The Clenched Fist of Hate appeared as a non-player character within the 2003 video game Star Wars Galaxies. This massively multiplayer online roleplaying game was developed by Sony Online Entertainment and published by LucasArts, before the game's servers were shut down on December 15, 2011. The Clenched Fist of Hate was incorporated into the game as part of the "Exar Kun" Heroic Encounter, which was introduced with the release of the "Chapter 9" update on April 3, 2008.
Within the Temple of Exar Kun Heroic Encounter, the Clenched Fist of Hate functioned as a "boss" enemy NPC. He was the fourth encounter within the instance, following the Open Hand of Hate, the Minder of Weak Wills, and the Caretaker of Lost Souls.