"There's life in my bones yet. Make a run for it, Private; I'll keep them busy."
— F-9777 "Firewire"
Firewire, or F-9777, is a very old clone by human standards and especially by the standards of the Grand Army, who has a minimal life-expectancy at best for combatants. Originally a member of the Omega Airborne as a part of the 724th Infantry, Firewire earned his reputation as an eccentric clone a long time ago.
As a clone with a mental defect, that of obsessive tendencies bordering on being a danger to others, he would have been terminated long before he had a chance to enter combat, but the fact that his obsessive tendencies drove him to work almost to exhaustion in favor of his squad and the GAR made the Council reconsider and instead put him to use where his mental defect would do the most good.
These days, Firewire is admired by the lower ranking clones for being something of a 'grandfather' figure to a group of men who have no fathers or mothers. Usually he manifests his somewhat parental affections in the form of 'tough love' and sees education through participation as the only way to go. He is sometimes known as a brutal man with unshakable beliefs, and his refusal to adhere to certain GAR policies regarding the justice system has him carefully watched, but the higher-ranking clones above him tend to prevent harm from coming to him, because he himself helped train a majority of them.
Firewire's 'official' duties consist of research and development, and maintaining equipment in battlefield conditions. When a hovertank won't float, Firewire is the clone that runs into the front lines to get it moving again, heedless to weaponfire.
But when things look grim and the line is failing... the younger clones retreat to leave this engineer to mop up the mess with merciless efficiency. In his own words: experience is everything.