Dol Grenn was a Human male and a native of Telos IV who served as a lieutenant in the Telos Security Force. A grizzled, well-respected veteran, Grenn held to a staunch adherence to the law and devoted his life to seeing it upheld on Citadel Station as, in the wake of the Sith attack, it oversaw the Telosian Restoration Project. He was also an old friend of Carth Onasi, who was a native of that world as well; during the First Jedi Purge some five years after the close of the Jedi Civil War, the two communicated in regards to Meetra Surik. During the Battle of Telos IV, Lieutenant Grenn led the effort to defend the massive station against Darth Nihilus's attack until relieved by Republic forces under Admiral Onasi.
Dol Grenn was born on Telos IV a number of years prior to Admiral Saul Karath's devastating attack on that world. At an early age he dedicated himself to serving the law on his homeworld, joining the Telos Security Force and eventually earning the rank of lieutenant and, at some point, befriending longtime Republic star pilot and officer Carth Onasi. After the scourging of its surface by the Sith Empire under Darth Malak, Grenn continued to do the best he could to keep the peace in the few communities of native Telosians that remained.
Upon their arrival on Citadel Station in 3951 BBY, during the First Jedi Purge and in the wake of the Peragus Mining Facility's destruction, Lieutenant Grenn confined Meetra Surik and her companions, Atton Rand and Kreia, to the station for the duration of the Republic's investigation of the disaster. This was after having held them briefly in a TSF force cage and under house arrest pending the Telosian Council's own preliminary examinations. While being held in the TSF station, an assassin, disguised as TSF officer Batu Rem, infiltrated the holding cell room and attempted to kill the party. When he was defeated, Grenn initially thought that Surik was attempting to escape; however, when the true nature of the bounty hunter in disguise was determined, he took it very seriously, assuring the party that such an infiltration would have been very difficult and that there would be no repeat incidents.
Some time later Surik, with the help of the Ithorian herd who had initially overseen the Telosian Restoration Project, was able to escape to the surface of the planet unnoticed by Grenn and the rest of the TSF, leaving the station via an orbital shuttle in search of her starship, the Ebon Hawk, which had been stolen from a TSF impound dock.
However, she eventually returned to Citadel Station to again meet with Grenn, bearing an offer from Vogga the Hutt to ship fuel from Sleheyron in order to keep the titanic space station in orbit around the planet as well as to continue surface operations for the project. Prior to her flight to the surface, Surik also aided Grenn in uncovering the source of a modified holdout blaster, which led to the busting of a large smuggling ring on the station controlled by Samhan Dobo, as well as performing other work for him. This included tracking down a pair of dangerous criminals and securing the testimony and safety of Batono, an ex-Czerka Corporation employee who had evidence of the corporation's wrongdoing.
Unfortunately, Lieutenant Grenn and the TSF appeared to be largely powerless. Not only could they not prevent the Ebon Hawk from being stolen, but the TSF officer Batu Rem had been kidnapped while on leave and replaced by an assassin who, while working out of Nar Shaddaa, infiltrated the station and the TSF in the hope of collecting the bounty on Surik's head. The TSF was also unable to stop the rapid spread of the Exchange aboard Citadel Station, as well as keeping the mercenary population in check. On the other hand, the TSF suffered from excessive bureaucracy from within the Telosian Council, a severe lack of trained personnel, as well as a lack of funding. Despite this, Grenn and his officers did the best they could with what they had.
Later that year, Grenn was forced to command a military defense of Citadel Station when Darth Nihilus attacked Telos IV. Coming out of nowhere, the Ravager and a fleet of Sith warships decanted from hyperspace in the space above Telos. Having command of only a small force, Grenn sent out a series of requests for help. A force of Khoonda militia arrived, commanded by Zherron; in addition Queen Talia sent a contingent of soldiers from Onderon, led by the newly-promoted Major Riiken, to assist in the situation. Meetra Surik, who had only just arrived herself in pursuit of Darth Traya, lent her and her companions' assistance to the defense; she personally led the charge toward the TSF Headquarters, preventing the sabotaging of Citadel's fuel systems by several Sith soldiers and Dark Jedi in the process. With the situation on the station stabilized and with Republic reinforcements, led by Admiral Carth Onasi aboard the Sojourn arriving in-system, Surik, along with Mandalore and Visas Marr, made her way to the Ravager via a small transport shuttle and destroyed the ship, forcing the Sith fleet to retreat. Upon arriving back on-station, Grenn greeted Surik with a message from Admiral Onasi, requesting an audience to discuss a "mutual acquaintance," which turned out to be Revan.
Dol Grenn was, for all intents and purposes, a dedicated defender of the law. Though he wore the face of a hard-bitten, veteran enforcer who held to strict interpretations of the policies and guidelines of the government of the rebuilding Telos, he was not afraid to venture outside the system in order to get things done; this was evidenced by his willingness to accept help from Meetra Surik in resolving situations that the Telosian Security Force was otherwise powerless to address. Grenn maintained that, as a soldier, he was not the sort to be able to make agreements and perform other kinds of diplomatic duties, which he thought would be necessary in order to relieve the station's fuel shortage in the wake of Peragus's destruction. Though not one to mince words, Grenn always kept his word, and was mindful to always reward successful efforts accordingly. He also tended to hold a rather jaded view of the general state of the Republic, a view that he was not afraid to speak aloud when the opportunity presented itself.
Many of the tasks that Grenn offers for completion are optional, for example the seeking out of Batono and finding the identity of the assassin who tries to kill Meetra Surik and her companions. In addition, if the player takes the dark path, they can choose to subvert the TSF efforts on Citadel Station by doing Czerka's work when it comes to Batono; i.e., killing him or turning him over to Jana Lorso. If the player continues along the dark side path, then Grenn merely comments on Surik's appearance when she returns to Citadel Station to fight against Nihilus' forces, asking if she had contracted some sort of plague.
- Star Wars: Knights of the Old Republic II: The Sith Lords: Prima Official Game Guide
- The Complete Star Wars Encyclopedia