They first appeared in the U.S. state of Kentucky. Cannonball's younger sister Joelle Guthrie had joined the organization in hopes of people recognizing her specialty and as sort of a rebellious act against her older brother and sister Page ( Husk) whom where both mutants and X-men heroes. The organization had a large compound where meetings where held. The arrival of the X-men ruined some of their plans, but the organization told the X-men they where a legal organization and already called the police, because the X-men had invaded their private property (not taken the fact that the organization had seized and almost killed Husk the moment Cannonball and Husk came into the compound to bring their sister back.
After the initial encounter, the organization became more brutal and started illegal activities, even killing mutants.
A man named "Trask" appeared to be the leader of Humanity's Last Stand, witch happened to be the same name as Bolivar Trask, the man who created the Sentinels, but died soon afterwards. First it was unknown whether this was the real Trask that somehow survived his seeming death or another person entirely. It was later revealed that this Trask was actually Simon Trask.