Clone Commander "Keller" led a unit of clone troopers on Toola during the Clone Wars. The unit took part in an assault on the CIS's main generators on the planet alongside Jedi Generals Simms, Kai Hudorra and Jedi Commander Noirah Na.
At the onset of the Outer Rim Sieges, Keller's unit was sent to the frigid planet of Toola to combat CIS forces stationed there. After weeks of stalemate against the separatist forces, Jedi General Kai Hudorra, Jedi General Simms, and Kai's padawan launched an assault on the droids' main generators with a small portion of the unit, while the rest of the clones staged a diversionary attack.
Their ploy was successful, but shortly after, Clone Commander Keller received orders to execute Order 66, and the clones started firing upon their Jedi leaders. The clones were successful in killing one of the Jedi, but Kai Hudorra and his padawan fled on Single Trooper Aerial Platforms.
Shortly after, Keller and his unit tracked down the two Jedi to Ithaqua Station, a small civilian port on the planet. Once they reached the station, Keller and his men started searching for the two missing Jedi, raiding as many places as they could and asking people for their identification papers. After reaching a small bar where Hudorra was drinking, Keller and two of his men started asking around for identification. But, Hudorra managed to get away by convincing the patrons to attack the clones under the pretense that the war was over and that they had no right to hassle innocent civilians anymore.
Keller's Unit kept searching Ithaqua Station, but never found the two Jedi as they managed to get away on a transport to Coruscant after sneaking into Toola Spaceport, and tricking one of the troopers into letting them aboard the ship.
Troopers in Keller's unit used white Galactic Marine armor with a single yellow stripe on each pauldron and standard phase II clone trooper armor. They were also equipped with DC-15A blaster rifles and DC-15S blaster carbines. Some troopers also rode Mastmots equipped with two turrets mounted on the sides.
- Star Wars: Republic: Into the Unknown (First appearance)