Alpha is the seven founding members, all of which have extraordinary power. Next in command is Beta.
The leader of Alpha and the Legion is Codex, aka John Blake. He has unlimited magical abilities and immortality. He serves as the United States' Secretary of Meta-human Law Enforcement and Defense , is a member of the President's cabinet, and is an honorary United Nations member. He leads the Legion with a clear head, using tactics, never emotion and never kills.
The second in command is Hunter, aka Alex Drake. He has increased stamina, strength, endurance, speed, and agility. He is the weapons specialist of the Legion, and the main trainer. He uses his raw anger and rage to fight crime, scaring criminals and making them fear his name.
The third member is Heatwave, aka Thomas Brown. He has pyro-kinesis, the ability to manipulate fire and heat. He is one of the temperature meta-humans, and has started a romantic relationship with the other. He is fun-loving, and always looks for the next thrill.
The fourth member is Snow Angel, aka Jennifer Blake, Codex's younger sister. She has cryo-kinesis, the ability to manipulate snow, ice, and cold. She is the othe temperature meta-human, and is in a romantic relationship with Heatwave, despite their counter-acting powers. She is energetic, powerful, and extremely easy to tick off.
The fifth member is Plasma, aka James Reeds. He has the ability to control, absorb, or project any type of energy, both physcial and mental. He is the energy specialist and back-up generator for the GuardTower. He is a go-getter type of guy, always looking for something to do.
The sixth member is Argus, aka Theresa Richards. She has Omni-vision, the ability to see literally everything at once. She is the mission coordinator as well as communications officer. She's a know-it-all, and a bit of a show-off. Her and Codex seem to have a strong relationship, but nobody knows if it's romantic or not.
The seventh and final member is Drain, aka Amy Renner. She has the ability to absorb another meta-humans powers. Unfortunately, she was killed in the Great War by a squadron of Mandroids. She was a clumsy, shy, and passive girl in civilian life, but in combat, she was focused, tactical, and made the ultimate sacrifice to save the Legion.
The seven have been interviewed about their experiences in the Legion.
Codex has made a personal blog about what goes on with the Legion.