Roy Mustang, for most of the series is a colonel. He oversees Riza Hawkeye, Jean Havoc, Heymans Breda, Kain Fuery, Vato Falman, and Edward Elric. He fought in the Ishbalan Civil War, during which he decided what was being done was wrong. This started his goal to become the leader of the country to change it so that it would never happen again.
He recruited Edward Elric, and initially his brother Alphonse Elric as well. He was allegedly searching for their father Hohenheim and visited the boys the morning after their attempt at human transmutation.
He later stages a coup and kills the Fuhrer King Bradley, in the fight losing one of his eyes.
In Conqueror of Shamballa he has left behind his rank, his alchemy, and everyone behind and is working as an enlisted man in the North. During the attack on central by Dietlinde's forces he has returned and helps out.