Edward Elric
The main protagonist, Edward ("Ed") Elric is the famous Fullmetal Alchemist, though Al is occasionally mistaken for him because of his armored body. He has a prosthetic automail arm and leg, is of short stature, and typically reacts in an exaggerated manner to any remarks about his height. He is known for being the youngest State Alchemist, gaining this title at the age of 12.
Alphonse Elric
Alphonse, often nicknamed "Al," is Fullmetal Alchemist's secondary protagonist; he is Edward's younger brother and the narrator of the series. For most of the series his soul is trapped in a large suit of armor, causing other characters throughout the series to confuse Al with the "Fullmetal" Alchemist. Alphonse is the calmer of the two, and can be seen as a foil to Edward's character.
Colonel Roy Mustang
Roy Mustang is known as the Flame Alchemist. His gloves are made of a special material called "ignition cloth," which allows him to create a spark by snapping his fingers. He then uses alchemy to change the oxygen density in the air with the help of transmutation circles on his gloves, causing a controlled explosion. He is Edward's direct superior officer in the military, but has his own goal, mainly to become the Führer, leader of the military.
Winry Rockbell
Winry is a mechanical expert who is a childhood friend of the Elrics. She, along with her grandmother Pinako, built Edward's automail, and she also helps maintain the automail when it gets broken. Her parents were called into service as doctors for the Ishbalan Civil War and were killed.