The 38th Ranger Expeditionary Force (38th REDF), nicknamed "38 Ranger", was a UNSC Ranger Corps expeditionary force and joint strike force attached to UNSC Special Operations Command Centauri (UNSCSOCCEN) and active in the Sol Theater of Operations, specifically on the colony Earth, the Human homeworld and UNSC capital planet. 38 Ranger would later participate in the Necros War.