Alexander Lexington served in the military. He kept his mutant powers a secret. While he was a skilled soldier, he also had a long disciplinary record.
Lexington was recruited into the Sentinel Squad training power. He was forced to use his powers during training although he and Meld were able to hide the fact for a while.
A mission in the Savage Land ended in the deaths of most of the trainees. Lexington was able to successfully free James Rhodes and escape.
Lexington lost his mutant powers due to M-Day, and is currently the Sentinel Squad O*N*E field captain.