How some of Rex's closest friends respond when asked "Who is Captain Rex?":

Cody: A freakin' nerd

Anakin: My right hand man

Ahsoka: The guy who tells me where Anakin hides his candy stash

Obi-Wan: One of the bravest men I know

Wolffe: A guy with a spine of steel, but that spine is actually the stick shoved up his ass

Cody, again: A total freakin' NERD