Alex Louis Armstrong serves as a State Alchemist and Major in the Amestrian State Military, renowned as the "Strong Arm Alchemist" for his signature combat approach. Towering at 212 cm, he possesses a powerfully muscular build. His distinctive appearance features a bald head with a single blond curl above his brow, a prominent handlebar mustache, a cleft chin, blue eyes, and absent eyebrows. He often tears his uniform to flex his muscles during emotional outbursts, battles, or motivational efforts. Hailing from the prestigious Armstrong family, he deeply reveres his heritage, consistently attributing his abilities to traditions "passed down the Armstrong line for generations." His sisters include the formidable Major General Olivier Mira Armstrong, toward whom Alex shows profound respect and affection, enduring her harsh critiques—especially concerning his perceived failures in the Ishvalan Civil War—with unwavering politeness. Their relationship evolves into mutual respect through later conflicts. Despite his imposing size, Armstrong exhibits a softhearted, highly emotional nature. He cries readily at sorrow, compassion, or joy, prioritizing the protection of innocents and allies. This compassion manifests as overbearing concern for younger individuals, particularly Edward and Alphonse Elric, whom he mentors and safeguards. His kindness contrasts with his combat prowess; he avoids lethal force when possible, a principle rooted in trauma from the Ishvalan Civil War. As a young officer there, he refused orders to trap Ishvalan civilians for execution and later spared an Ishvalan woman and her mother, leading to a breakdown. This instilled lasting guilt over his inaction, driving his commitment to redemption through service. Armstrong's alchemy fuses physical combat with transmutation. Using customized metal gauntlets inscribed with transmutation circles, Hebrew text for "God," and German poetry, he channels kinetic energy from strikes into alchemical reactions. This enables rapid creation of stone projectiles, spikes, walls, or platforms. His signature techniques involve generating artillery-like stone darts and erecting multi-story barriers, proving effective against foes like the Homunculus Sloth, whom he fought alongside Sig Curtis. Beyond alchemy, he displays exceptional physical strength and endurance, weathering severe impacts and fighting evenly with adversaries like Scar. He also demonstrates diverse talents such as portrait painting, tracking, and wood-chopping, often crediting these to his lineage. Professionally, he collaborates with Colonel Roy Mustang, maintaining uncharacteristic formality while providing tactical support. Armstrong's development centers on reconciling pacifist ideals with his soldier's role. His resolve hardens during the conflict against the Homunculi, culminating in his confrontation with Sloth to protect his sister and allies, symbolizing his vow to never again "run away" from moral duty.