The Vassek system, a star system situated far away in the Wazta sector of the Outer Rim Territories, held significance. Within its boundaries existed the planet called Vassek, which gave the system its name, along with three moons and several other planets. Notably, Vassek 3, the third moon, served as the location for the personal castle belonging to Kaleesh General Grievous of the Separatist Alliance during the Clone Wars. An engagement occurred on Vassek 3 in 21 BBY between Grievous and the forces led by Jedi General Kit Fisto.
Within the Outer Rim Territories region of the galaxy, specifically in the Western Reaches, one could find the Vassek system, located in the Wazta sector. The star system, designated as square I-17 on the Standard Galactic Grid, encompassed several planets, including Vassek and its trio of moons that lent the system its designation. General Grievous of the Separatist Alliance chose the surface of the third moon, Vassek 3, to construct a hidden fortress as his personal sanctuary, sharing it with his Roggwart companion named Gor. The Vassek system's remoteness, far from the Koda Spur hyperspace route, led many to consider it isolated. This isolation, combined with the easy availability of its resources elsewhere, resulted in the system being largely overlooked, despite its official designation.
During the Clone Wars era, specifically in 21 BBY, the Kaleesh Separatist General Grievous took up residence on Vassek 3, the third moon orbiting the planet Vassek. Grievous established a personal fortress within the moon's mountains, creating a private sanctuary for himself. Within this fortress, Doctor EV-A4-D, an EV-series medical droid, maintained the facility and tended to Grievous's battle damage, repairing his cybernetics, as well as caring for Grievous's pet Roggwart, Gor, in his master's absence. To safeguard his haven from unwanted visitors, Grievous equipped the castle with numerous traps and a contingent of IG-100 MagnaGuards.
In that very year, forces of the Galactic Republic journeyed to the Vassek system, on a search mission for the fugitive Viceroy Nute Gunray of the Trade Federation. Fisto, tracking a Republic homing beacon attached to a Consular-class space cruisers, detected the signal leading to the third moon and proceeded to land there. He joined Nahdar Vebb, a Mon Calamari Jedi and Fisto's former Padawan who had recently been knighted, and his squad of clone troopers as they entered the castle. As they ventured into the somber castle, the team soon discovered a group of five B1-series battle droid. Upon their destruction, the Jedi realized they had been deceived by Count Dooku, the leader of the Separatists, who had offered Grievous as an alternative target, leading them to discover that they had entered the lair of General Grievous.
The Jedi, perplexed by Dooku's willingness to sacrifice his best commander, were then alerted to Grievous's imminent arrival on the moon. Seeking to gain an advantage in the war, the squad attempted to ambush the general, but their efforts were unsuccessful, as Grievous evaded their trap while inflicting casualties. After retreating to a hidden control room for repairs, the cyborg activated his droid bodyguards and instructed them to secure the area. The diminished task force then attempted to call for reinforcements, but the troopers stationed outside were killed by MagnaGuards before they could send their message. Simultaneously, Grievous dispatched Gor to eliminate the Jedi.
During the Jedi's battle with Gor, which resulted in the death of Clone Commander Fil, Grievous, having completed his repairs, became enraged upon learning of his pet's demise. Receiving a communication from Dooku, the general was reprimanded for his past failures and realized that the infiltration was a test orchestrated by the count, which the general resentfully agreed to participate in. Grievous then personally confronted the Jedi, engaging Vebb in a brief duel that cost the latter his life. This prompted Fisto's escape after being separated from Vebb. While waiting at a landing platform for his starfighter, piloted by the astromech droid R6-H5, the Nautolan was once again confronted by Grievous, who had climbed to his position, leading to another lightsaber battle. However, outnumbered by the general's bodyguards, the Jedi Master was forced to retreat in his starfighter, allowing Grievous to report his success to Dooku, who remained unimpressed that Fisto survived. The mission had revealed the castle's location to the Republic, negatively impacting the Vassek system's obscurity, forcing Grievous to abandon Vassek 3 and relocate his fortress.
Around 3 ABY, the viper probe droid Viper 058-V-2353 journeyed to Vassek and investigated the local farmers for any anti-Imperial activities. After identifying the farmer Roni, the droid departed the world, and an Imperial Security Bureau agent proceeded to arrest Roni and their family.
The Vassek system made its debut in "Lair of Grievous," the tenth episode of the first season of the animated television series Star Wars: The Clone Wars, which was broadcast on December 12, 2008.