Frank Archer (フランク・アーチャー, Furanku Āchā) is a character exclusive to the anime, introduced as the replacement of Maes Hughes. He is cool, calm, and collected, with a love for violence and war. He dreams of becoming a hero on the battlefield, viewing it as a way to rise up the ranks of the military. To this end he does whatever is necessary to please his superiors and always insures that his actions earn him some publicity. As the series progresses, Archer develops an interest in the military's various projects, such as the homunculi, the chimera, and the Philosopher's Stone. His ambitions of gaining the latter cause the left half of his body to be used in its creation, forcing him to undergo automail modification to regain his mobility. The operations leave him mentally unstable and he rages through Central while carrying out King Bradley's ordered executions, stopping only once killed by Riza Hawkeye.

Source: Wikipedia