Agent C is a chicken which works for The Agency, apparently in Major Monogram's division. Her first name is unknown as she only appears in the series for brief moments. not much is shown of her but she was seen in "Traffic Cam Caper". She was also seen in "It's About Time!", where she pecked at one of the evil scientists.
At the end of the episode "Traffic Cam Caper", Agent C is seen trying to eat another Agent, Agent W, a worm. Whether this was just to tease the little agent, or that Agent C's natural instincts was making her attack her own allies is unsure.