The Assault on Base Prime represents an offensive maneuver executed by the New Jedi Order targeting the Columi siblings, Craitheus and Marvid Qreph. The operation's dual objectives were the liberation of Han Solo and the prevention of the brothers' access to a specific monolith that served as the foundation for Base Prime.
In the year 45 ABY, the Columi brothers, identified as Craitheus and Marvid Qreph, made a significant discovery: an unidentifiable monolith situated at the core of the Chiloon Rift. Capitalizing on this find, they constructed a fortress known as Base Prime directly on top of the monolith, positioning it above a Space–time-warping gate that provided entry to the monolith itself. Their study of the monolith revealed its unique capability: granting individuals who entered it the powers associated with the Force. To secure their plans for the monolith without external interference, they orchestrated a hostile takeover of the Chiloon Rift through illicit business practices. These actions inevitably led to conflict with the New Jedi Order. As tensions escalated, the Qrephs took Han Solo, a Jedi ally, captive. Solo was imprisoned and subjected to torture at Base Prime as the Qrephs prepared to enter the monolith. However, before they could proceed, the Jedi discovered the monolith's existence and initiated an assault with the goals of rescuing Solo and neutralizing the Qrephs' plans.
The Qrephs had fortified their base, employing the biotically engineered species known as the Nargons for defense. To command their forces, they enlisted Mandalorian warriors under the leadership of Mirta Gev. However, upon the Jedi's arrival to attack, the Qrephs' Force-sensitive operative, Vestara Khai, operating under the alias Savannah Raine, persuaded the brothers to entrust her with leading the defense. Vestara, however, had underestimated the speed and effectiveness of the Jedi assault, particularly their deployment of YVH-Series battle droids. The Jedi swiftly breached the base's defenses, forcing Raine to order a retreat. She facilitated the Qrephs' evacuation through their residence to evade the advancing Jedi forces, but Craitheus sustained severe injuries during the maneuver. Marvid, frustrated by Vestara's interference, betrayed her by shooting her in the legs and proceeded towards the gate to access the monolith.
Mirta Gev, recognizing the inevitability of defeat, chose to assist Vestara in escaping Base Prime aboard her vessel, the Sith Meditation Sphere, Ship, abandoning the Qreph brothers to face the Jedi alone. She instructed her Mandalorians to desert the Nargons and flee. As the Jedi gained control of the base, Vestara and Gev utilized Ship to make their escape. Ben Skywalker, leading the Jedi forces, conducted a thorough search of the base for Vestara and Gev, but was unsuccessful in locating them. With the battle concluded, the Jedi destroyed Base Prime and established a secure perimeter around the monolith to prevent any further interaction.
Leia Organa Solo and Luke Skywalker pursued the Qrephs into the monolith and successfully defeated them, but they were unable to locate the Qrephs' agents.