Raynor's Rangers were a unit within the Sons of Korhal led by Captain Jim Raynor. It included numerous members of the former Mar Sara Colonial Militia.
History
The Rangers took part in combat against the Terran Confederacy in Tarsonis City, Tarsonis. It was accompanied by reporter Michael Liberty and ghost agent Sarah Kerrigan.
Following the use of psi emitters and the abandonment of Sarah Kerrigan, the Rangers revolted against Mengsk and Duke, with the assistance of Michael Liberty. When the soldiers tried to leave, they were stopped by Duke and a cohort of neurally resocialized marines. Liberty wounded Duke, prompting Duke's suit to inject him with painkillers that caused him to fall unconscious. Without orders, the marines took their leader to a medical facility.
The Rangers tried to rescue Kerrigan at New Gettysburg but failed as increasing zerg activity forced them to flee the planet. They managed to rescue terrans from a variety of affiliations and rendezvous with former-Confederate battlecruiser Thunder Child. They refused to rejoin the Sons of Korhal, now the Terran Dominion and became Raynor's Raiders.
References
Grubb, Jeff. StarCraft: Liberty's Crusade. Pocket Books, February 27, 2001. ISBN 0-671-04148-7.