Insurrectionist
From Halopedia, the Halo wiki
The Insurrectionists, otherwise dubbed as Innies by the Marines, were the UNSC's main enemy before the events in Halo: Contact Harvest, where the Covenant quickly became the new antagonist. The insurrectionists would deal supplies with the Jackals in the early stages of the Human-Covenant war. As depicted in Halo: The Cole Protocol. They could be referred to as terrorists, due to them only impeding the UNSC's progress to colonize and prosper.
Operation TREBUCHET was one of the largest and farthest reaching operations ever conducted in UNSC history. It was devised in order to rid the galaxy of the Insurrectionists, once and for all, but was promptly abandoned following the beginning of the Human-Covenant War.
Insurrectionists were present far beyond the Outer Colonies. They colonized and inhabited Hesiod, the only Rebel colony not to have been destroyed by the Covenant. The Insurrectionists protected refugees from other colonies at The Rubble, where an uneasy truce existed between the humans and the Kig-Yar, who were the original inhabitants of the asteroids.[1].
