Sigma

"Agent Maine, isn't that the soldier from the freeway? The one that shot you in the throat?....I thought so. Sic' em."

Sigma was an A.I. who originally belonged to Agent Carolina, however she gave him to Maine so he could communicate after an injury. Sigma learned that a full A.I. would be considered human based by just how they were capable to be sentient and experience all emotions; but for sigma, he was only a fragment of an A.I. and so, only had creativity and ambition. Sigma believed that if he gathered all of the fragments, he could put them back together so that they could become one and human.

So, Sigma took advantage of being in the brute, Maine, and possessed him. He forced Maine to kill his friends to steal their A.I. With every one of them he grew stronger and stronger, but ultimately was killed in the end.