Tolamyn Cayble was an Imperial Security Bureau agent who operated in the Elrood sector during the Galactic Civil War. A clever and confident intelligence operative, Cayble had a good field record and he was responsible for the elimination of several Rebel Alliance factions in the Elrood sector, keeping Rebel activity in the region to a minimum. After the Rebel agent Shondra Del attempted to broker an alliance between the Rebels and the Khuiumin Survivors pirate group, Cayble oversaw an operation that resulted in her capture. A short time afterward, Cayble and his fellow ISB agent Dineas D' Ink directed an Imperial raid on the base of the Friends of Paran resistance group in the city Knellis, on the planet Derilyn. In the aftermath of the attack, Cayble feared that the resistance group would attempt to sabotage the Derilyn Space Defense Platform, so he sent thirty ISB agents to defend the installation.