Red Faction and Dead Space take place in the same universe.Both universes have an Earth Defense Force that has space vessels capable of long distance travel. Given that there is no mention of Earth in Red Faction: Armageddon, it would make sense that Earth rather than give in to the miners of Mars found another, if more expensive way to extract ore and Mars became a Rogue State, while Earth went on to explore the galaxy and eventually come into contact with the Necromorphs.
Randy Jenkins is a brain-damaged EDF officer.Randy Jenkins is the crazy guy in the puffy red vest who drives you around while you blow up EDF property with rockets. He constantly rambles on about all manner of nonsensical topics while you do, exploring philosophy, independence, and politics in his own demented way. But it's clear as time goes on that nobody in the Faction really likes the guy because of his psychopathic nature and nonsensical rambling, and while his guerrilla actions are great for undermining the EDF they're not great for morale - His appetite for destruction and occasional disregard for civilians is more in line with how the EDF operates than the Faction. Well, if you look at the War Memorial in Eos (assuming you didn't blow it up) and read the names, you'll see Second Lieutenant R. Jenkins listed on there. Jenkins may very well be an ex-EDF officer who took a severe head injury and was assumed killed, but later recovered and, angry at the EDF for abandoning him, joined the Faction. Or he joined the Faction as a deep-cover agent to make them look bad with his reckless destruction, and once they start trusting him, he sells them out to the EDF Just as Planned.
- The original Red Faction took place 50 years before Guerilla. If Jenkins was old enough to be a soldier back then, he'd be in his 70s by the time Guerilla takes place.