The Drill Sergeant, is a gruff, stern drill sergeant who controls the Smile Away Reformatory School and its prisoners. He poses a very real threat to Phineas and Ferb. He loathes imagination and creativity and, through his reformatory school, attempts to remove these things from the children that are sent to him. As such, he is a natural antagonist to the Flynn-Fletcher boys, who find themselves under his control when Candace finally succeeds in busting them.