With the help of Aldrich Killian, A.I.M.'s leader, Maya Hansen semi-stabilized Extremis and also started to recruit amputees and other disabled people, most victims of military ops, as test subjects. In many of those tests the test subjects went unstable causing explosions in the A.I.M. facilities.
Many Extremis Soldiers went unstable and blew up, one of those soldiers was Chad Davis. This explosions caused A.I.M. to hire an actor named Trevor Slattery to portray the Mandarin and use him to make this explosions look like terrorist attacks.
An Extremis Soldier named Eric Savin met with another test subject to make an exchange, there Savin was confronted by Happy Hogan. Later the other test subject became unstable and blew up severely injuring Hogan and Savin. Savin later regenerated due to Extremis and left the place. The next day Savin led a team of heavily armed choppers to destroy Tony Stark's mansion.
In Rose Hill, Tennessee an Extremis Soldier named Ellen Brandt was sent to recover a set of documents from Mrs. Davis, there she found out that Tony Stark had already collected them and tried to get them, but failed.
As part of a trap to acquire the Iron Patriot Suit an Extremis Soldier was sent to Pakistan disguised as a sweat shop worker where she used her powers to disable the suit. Later, after A.I.M. acquired the suit, Savin was sent inside it to the Air Force One to kidnap President Ellis.
During the Battle on the Norco some Extremis Soldiers found Stark and James Rhodes in the Norco when they were trying to rescue Pepper Potts and President Ellis. Stark told J.A.R.V.I.S. to target all extremis heat signatures and destroy them using the Iron Legion. In the battle the Extremis Soldiers destroyed some of the Iron Man armors and were killed by them.