Gunnery Sergeant Hartman

Gunnery Sergeant Hartman is a major character in the anti-war film, Full Metal Jacket, although his role is that of an anti-hero he does become a significant antagonist who undertakes in illegal and abusive techniques even for the brutal time period and training of Marines : most notably his singling out and bullying of Pyle, who Hartman failed to recognize as mentally unstable and thus pushed to a breaking point that endangered the entire platoon and ultimately cost Hartman and Pyle their lives.

Personality
Hartman was a vicious, abusive drill instructor though most of his personality was necessary as his role - he did, however, partake in actions that were illegal even by the standards of Marine training, such as punching recruits and slapping them (drill instructors are not permited to use physical violence against recruits) : he also had no qualms about singling out specific recruits, such as Pyle - who he treated especially cruel, though Hartman was trying to help Pyle in his own manner, the critical failure of Hartman was that he could not see when his methods went too far and ignored the danger signs of Pyle losing sanity.

Hartman was unable to change his belief that intimidation and fear commanded respect, even when faced with a psychotic Pyle and thus instead of trying to reason with Pyle or seek alternative ways to defuse the situation he deliberately provoked Pyle and thus endangered not only himself but the entire platoon, showing that he was stubborn to the end.