Callan Grayne was a male Human who fought for the Republic Army during the Great Galactic War against the Sith Empire. He later rose to the rank of general within the Republic Strategic High Command during the subsequent Cold War. As the Galactic War erupted at the end of the Cold War, Grayne was deployed to the icy planet of Hoth to command the Republic forces stationed there. While overseeing the Republic Military operations on Hoth, Grayne sought assistance from the Jedi Knight known as the Hero of Tython, and later, following orders from fellow High Command member Durant, he assigned Sergeant Fideltin Rusk to support the Jedi.
Callan Grayne, a male Human, enlisted in the Republic Army sometime after 3665 BBY and was assigned to a squad that included the Chagrian Fideltin Rusk. These two individuals served together for a period of time during the Great Galactic War against the Sith Empire, participating in battles such as the Geonosis campaign, where they collaborated with a Human named Durant. During his service with the squad, Grayne sustained an injury in combat that resulted in the loss of his entire left leg; however, doctors provided him with a highly realistic prosthetic.
The conflict concluded in 3653 BBY with the signing of the Treaty of Coruscant, and during the subsequent Cold War, Grayne attained the rank of general within the Republic Strategic High Command, the highest command echelon of the Republic Military. Around 3642 BBY, Grayne was sent to oversee the Republic military forces on the planet Hoth, which had become a battleground between the Republic, the Empire, and the White Maw pirates in a three-way battle. These factions were fighting for control of the derelict starships and experimental technologies scattered across the planet's surface since the Battle of Hoth which occurred over a decade earlier in 3665 BBY. Upon arriving in orbit, Grayne was informed of the presence of several Imperial weapons platforms located near Crescent Canyon, a location situated close to the Republic's Aurek Base on the western edge of the Icetromper Wastes. Discovering that two Jedi Knights, Leeha Narezz and the Jedi known as the Hero of Tython, had taken command of the 301st Infantry for a covert mission, Grayne contacted the Hero. Remembering that General Var Suthra had praised the Knight's military skills, Grayne requested the Jedi's assistance in destroying the emplacements and neutralizing the threat they posed.
Shortly after, Grayne was notified that Rusk, now a sergeant in the 301st, was planning to assault a White Maw base in the Glacial Fissure region as part of the Jedi mission. Consequently, he instructed Rusk's squad to destroy several nearby munition dumps to weaken the White Maw's position. Following the Jedi's successful completion of the mission, Grayne consulted with General Durant from High Command. They jointly decided to rotate the 301st Infantry back to the Republic capital of Coruscant and replace them with the 88th Armor. However, Durant also made the decision to permanently assign Rusk to the Hero to provide assistance. Grayne then requested a meeting with Rusk's squad and the Jedi at Aurek Base. After briefly reminiscing about their shared past, the general communicated Durant's orders to Rusk, before returning to his duties of overseeing the battle against the Empire on Hoth.
Due to his experiences during the Great Galactic War, Grayne had a prosthetic left leg. On Hoth, he wore combat attire in shades of gray, white, and maroon that was suitable for the cold climate.
Callan Grayne is a character in Star Wars: The Old Republic, a video game developed by BioWare and published by LucasArts in 2011. He plays a recurring role in the Hoth storyline for players choosing the Jedi Knight class. Grayne initiates contact with the player during the "Suicide Squads" mission, requesting assistance in destroying nearby weapons emplacements. Sergeant Rusk then contacts the player in the "Position of Power" mission, adding the objective of targeting munitions dumps. Grayne makes a personal appearance at the conclusion of "The Price of Victory," where he assigns Rusk to the Knight, thereby granting the player their fourth companion character.