The post-apocalyptic descendants of the United States Marine Corps (or so they claim). They possessed an extremely high level of technology and resources, much of their technology has never been seen before or since in the New Nevada wastelands. Their soldiers were often highly trained and always suited in power armor. It was also believed that they may have been genetically modified. Various vehicles such as hovercraft and giant nuclear-powered tanks were also at their disposal.
The U.S.M.C. slowly made their presence known in New Nevada, making contact with various factions and occasionally taking prisoners. After demanding that Andy, leader of the New Nevada Desert Rangers at the time, turn over the Ranger Center to be used as their new headquarters and being refused, they attacked the RC. The Desert Rangers pulled in their allies and prepared to stand their ground. A hard-fought battle ensued, during which both sides took heavy damages and the U.S.M.C. lost much of their resources before retreating. However, splinter groups of U.S.M.C. were known to appear out of nowhere and cause havoc throughout the New Nevada wastes for some years afterwards.
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