Nimrod is a robotic android that was built by humans as ahead of its times. It's primary programming is to save humanity by eliminating mutants. What made the machine extremely dangerous was its ability to "learn".
Shatterstar and the rest of X-Force clashed with Nimrod while trying to destroy it. Shatterstar had tried to disable Nimrod with his sword, but he was unsuccessful. He tried to pair up with Domino by having him slice an opening in Nimrod while Domino implanted an explosive device in Nimrod, but still, it didn't work. Facing certain defeat, Siryn came in to help by disabling Nimrod with her sonic screams long enough to disable Nimrod, allowing Cable to enter Nimrod's mind and present Nimrod with the logical statement that if Nimrod was allowed to exist sixty years before it actually should have, incalculable damage to the enviroment and to humanity, who is supposedly should be protected by Nimrod, would be done, and Nimrod was defeated after it realized that it would be better for itself to be shut off and let humanity and mutants deal with the problem than to have itself enforce his programming.
