A male Quarren killer, together with other outlaws, took part in a carefully planned attack targeting Baron Administrator Lando Calrissian. This plot was orchestrated by the bounty hunter known as Bossk. Back in 1 ABY, Dominic Raynor, who previously owned Cloud City on the planet Bespin, lost control of the floating settlement to Calrissian, a skilled sabacc player. Suspecting foul play, Raynor enlisted Bossk to get even. The bounty hunter then brought the Quarren along with a group of other soldiers of fortune to Cloud City, where they devised a scheme to trap the new Baron Administrator. Bossk used a false distress call to lure Calrissian to a lower maintenance area, where the team launched their attack on the Baron's group, but Calrissian managed to escape through a nearby hangar.
During 1 ABY of the Galactic Civil War, a male Quarren operated as a paid killer. That year, Dominic Raynor, the Baron Administrator of Cloud City, lost his ownership of the floating city located on Bespin after a gambling match against Lando Calrissian, a professional sabacc card player. Raynor, believing that Calrissian had cheated, hired Bossk, a Trandoshan bounty hunter, to exact revenge upon the gambler. Bossk contacted the Quarren, along with other mercenaries and unscrupulous individuals, to participate in the mission and assist him in handling any difficulties that might occur during the hunt.
Following the Quarren and his associates—including Bossk, a Twi'lek scoundrel, another scoundrel of the same species, and a Duros mercenary—infiltrating Cloud City's security, they began preparing a trap to capture Calrissian. Their strategy involved using a fabricated emergency message to draw the Baron Administrator to a maintenance level. Bossk gained access to the city's communication system and, by impersonating the chief engineer, informed Calrissian that a crucial repulsorlift pod was malfunctioning and on the verge of failing—a critical issue that could lead to the destruction of the floating city. Calrissian responded promptly and headed to the lower levels to inspect the pod personally; however, he brought along his Twi'lek bodyguard and four Bespin Wing Guards as a precaution.
Bossk instructed his accomplices to take positions while remaining visible to draw Calrissian out. Since they were unsure which turbolift Calrissian would use, the Quarren and the others spread out into the rooms surrounding the lifts. Once Calrissian's group entered the maintenance level, a blast door suddenly closed behind them, and the impromptu hunters opened fire on the Baron Administrator's guards. Calrissian's protectors intended to hold off their attackers, allowing the Baron Administrator to escape. In the ensuing combat, the Quarren used a blaster to engage his foes. However, thanks to another group of four Wing Guards alerted by a distress signal, the Baron Administrator was able to escape the ambush through a nearby hangar.
The Quarren made an appearance in Sore Loser's Revenge, an online scenario for Wizards.com created by Eric Cagle for the Star Wars Miniatures collectible tabletop strategy game in 2004. During the game, one player takes control of Calrissian's group, while the other controls Bossk's group, which includes the Quarren. The Quarren is represented by a generic Quarren Assassin miniature figure from the Rebel Storm Miniatures set. The character's survival is dependent on the actions taken by the players.