Fullmetal Alchemist: Brotherhood - episode 30 - 31 Oct, 2009

Years ago, Mustang's desire to become a state alchemist was disapproved of by his teacher, Berthold Hawkeye, who was Riza Hawkeye's father. Before dying from an illness, he asked Mustang to look after his daughter, who has the details of his flame alchemy research tattooed on her back. In the present, Edward visits Hawkeye and returns the gun she lent him, explaining his inability to pull the trigger. After the civil war had broke out seven years past, Bradley signed a document announcing the extermination of the Ishvalans. It took a toll on many state alchemists and soldiers, including Hughes and Mustang, which was not helped by the taunts of the hardhearted Kimblee. Marcoh reveals to Scar that he was involved in using Ishvalans to make the philosopher's stone, which was given to the state alchemists to enhance their alchemy. The Ishvalan leader tried pleading with Bradley to end the killing in exchange for his life, but he was rejected. When the civil war finally ended, Mustang resolved that he would work to become the new Führer to protect the people, and appointed Hawkeye as his second-in-command. Hawkeye mentions to Edward that when they finally achieve peace, they may have to be punished for the crimes they committed during the war. When Envy checks Marcoh's prison cell, he finds a beheaded corpse and the word "vengeance" written in blood on the wall. (Source: Wikipedia)