Rebel

Rebels are any group that wants to break away from a primary government. "Rebel" may refer to the following:

In the UNSC:
 * Frieden - A secessionist faction that fought against the UN in the Interplanetary War.
 * Koslovics - The neo-Communist faction that fought against the UN in the Interplanetary War.
 * Insurrectionists - The general name for rebels during the Insurrection.
 * United Rebel Front - A prominent alliance of Insurrectionist cells.
 * Freedom and Liberation Party - A terrorist group active in the Eridanus sector.
 * Secessionist Union - A rebel union on Harvest led by Jerald Mulkey Ander.
 * Harvest for Harvesters - Another rebel group on Harvest.
 * Unidentified insurrectionist group - A rebel group active on Harvest and Arcadia.
 * Bandusa Insurrectionist group - An alliance of Insurrectionists with operations in the Sol system.
 * New Colonial Alliance - A post-Human-Covenant War rebel group.

In the Covenant:
 * Sesa 'Refumee's heretic faction - The breakaway faction that followed Sesa 'Refumee and was against the Great Journey.
 * Covenant separatists - The Elite-led faction after they learned the truth about the Halos.
 * The Grunt Rebellion - A Grunt uprising against the rest of the Covenant which led to the creation of an Arbiter.