Division 3

Division 3 is a secret tactical arm of the United States military, who are dedicated in the capture, study and sometimes terminate mutants. They served as the secondary antagonist in season 1 of Legion, alongside Shadow King (Legion).

After the first season they merged with the mutant group Summerland in order to fight the Shadow King and other dangerous mutants, and work on healthy mutant-human relations.

Structure
Division 3 works with Division 1 (Global command and communications) and Division 2 (Science, genetics, and technology). D3 serves as the "tip of the spear" and consists of 4 main branches:

Investigations: Responsible for tracking mutants.

Research: Responsible for discovering ways to deal with mutants with science and technology.

Strategy: Responsible for the organisation of plans and procedurals against mutants, as well as the general population.

Tactical: Soldiers responsible for the capture and/or termination of mutants.

The organisation is led by Admiral Fukuyama, a mysterious cyborg, though different arms have their own commanders as well, such as General Stanley in Tactical and Brubaker in Investigations. D3 is also known to use mutant agents such as Walter, who can command small teams, but always report to a human superior.

Season 1
Division 3, alongside Divisions 1 and 2, were founded after an event known simply as the "Lazarus Affair". They started capturing and killing mutants, though recurring some others, like Walter. A secret war broke out between Division 3 and a mutant group known as Summerland, with Division 3 quickly gaining an upper hand through numbers and technology (such as the "Peacemaker").

At some point Division 3 discovered and captured David Haller, a powerful telepathic mutant from Clockworks Psychiatric Hospital. Seeing the threat David could cause with immense telepathic powers, Division 2 ordered Division 3 to kill the mutant. David was broken out by a group of Summerland mutants who stormed the facility in which he was held, causing the death of dozens of Tactical officers and the injuring of Investigations Officer Clark DeBussey.

Division 3 continued to track the mutants, looking for their base, but then decided to catch David's sister Amy, hoping the telepath would come to them. David later did arrive, but with the help of the Lenny Busker (actually the Shadow King, who was possessing the telepath) he managed to free his sister and kill all D3 agents, including Brubaker.

Clark DeBussey, after recovering from his injuries, later managed to finally find Summerland with a Tactical task force, seeking to kill David as revenge for his own injury as well as all the agents killed by Summerland. The telepath still managed to incapacitate all of the Tactical agents with Clark, though refused to kill them. David revealed he wanted Summerland and Division 3 sigh a peace treaty and go after actual mutant threats such as the Shadow King. In the beginning Clark showed hesitation, though when he witnessed the power of the Shadow King showed after breaking away from David's mind and defeating several mutants, he agreed that he would talk with his superiors about the peace.

Soon after that Division absorbed Summerland, with several former mutant enemies now becoming agents of the Division, such as Sydney Barrett, Ptonomy Wallace and the Loudermilks.

Tirvia

 * Is an original concept developed for the TV series Legion.