Fullmetal Alchemist - episode 15 - 16 Jan, 2004

Armstrong reveals that Scar is an Ishbalan alchemist during their battle. Marcoh tells the Elrics about the Ishbal massacre, how state alchemists were used against the Ishbalans, who viewed alchemy as heretical. Marcoh, forced to use his research, caused huge casualties on the Ishbalan side. Mustang, forced to kill a pair of doctors, who were saving lives from both sides, allows Marcoh to desert. When the doctors are revealed to be Winry's parents, Marcoh refuses to escape to Resembool with the Elrics. Scar, fleeing from the military, runs into the Elrics again as they defend themselves against him, resulting in Scar destroying Ed's arm and damaging Al's body. Just as Scar prepares to finish off Ed, Marcoh throws his red stone at Scar, causing him to painfully absorb the stone into his tattooed arm. Outnumbered by military reinforcements, Scar manages to escape into the sewers and Marcoh is taken to a "safe location" by the Führer's personal secretary. (Source: Wikipedia)