As part of the U.S. government's efforts to stabilize the mutant situation following the advent of House of M|"M-Day", the Office of National Emergency (O*N*E) proposed to revive and retool the Sentinel program. To that end, the O*N*E contracted Stark Industries to upgrade existing Sentinels, as well as acquiring offensive and defensive improvements from S.H.I.E.L.D., to form a new breed of Sentinels designed to be operated by human pilots. This group of Sentinels is unique in that they are piloted, as opposed to the traditional robotic Sentinel. The current group was trained by James Rhodes (War Machine).
The Sentinel Squad program endeavors to train a new generation of controllable, dependable, repairable, replaceable, customizable, and loyal American heroes that are supervised by the O*N*E and trained to follow a military command structure.
Sentinel Squad O*N*E was deployed at the X-Mansion to protect the mutants in case any enemies used this low point as an opportunity to attack them at their weakest, and also to stop the mutants in the event of a revolution.