Rannos, a Human male, was an operative for the Republic Strategic Information Service, achieving the rank of Chief during the time of the Galactic War. Following the Tion Hegemony's fall to a rakghoul plague outbreak, Rannos became worried, and then sent his agent Whisper out to find and enlist Republic agents. Afterward, he commanded the Republic's assault that targeted Doctor Sannus Lorrick's Lost Island.
Republic players first encounter Chief Rannos in the Kaon Under Siege Flashpoint, which was introduced to the Star Wars: The Old Republic video game via Game Update 1.1. Fred Tatasciore provides his voice.