Alex Louis Armstrong (アレックス・ルイ・アームストロング, Arekkusu Rui Āmusutorongu), the "Strong Arm Alchemist", is a large and comically emotional State Alchemist. He will burst into tears or joyous praise given the right situation, and embraces others in an effort to console them. Because he is an extremely strong character, this usually causes others great personal injury. Armstrong is very proud of his strength and of his muscular physique, frequently taking off his shirt so that he can flex for others' benefit. As a final element of his comedic properties, he has the tendency to "sparkle"; when first appearing in a scene or taking off his shirt, pink stars radiate from his body. Despite his humorous tendencies, Armstrong can be very serious when the situation calls for it. He is not fond of violence and will try to end conflicts peacefully, and will break down and cry if an innocent person is killed.
Armstrong comes from a wealthy family of aristocrats who have earned renown in most professions. He has mastered many of his family's talents for himself, and when displaying such a talent he remarks it to have been "passed down the Armstrong line for generations". His alchemical skills are also a remnant of his family's history; by using a unique kind of brass knuckles, Armstrong can reshape any solid object that he punches. In addition to projectiles and barriers for combat purposes, he can use this talent to create buildings and at times sculptures of himself. Armstrong is a valuable ally of Roy Mustang and the Elric brothers, even if they are not always happy to be in his emotional company. He takes his honor as a soldier and as a leader seriously, and always looks out for his peers' and subordinates' best interests.