During the Golden Age Humanity created self-aware machines called Exo's meant to aid in the expansion and colonization of other worlds, then later deactivated. While during the Collapse, Humanity awakened their mechanical counterparts to help defend their worlds from the siege of the Darkness. One of those Exo's: Enigma-127, was reactivated on Mars just as the Cabal invaded the planet. Enigma along with the other exo's and human's valiantly fought against the giant war rhinos in an attempt to defend Mars. Eventually however, the tides turned against them and all who fought died including the ones who didn't. With Mars taken along with just about the rest of the Solar System, had it not been for the Traveler humanity and everyone else would've been slaughtered. Once the survivors built the Last City and once again set off into the stars to fight back the Darkness they found themselves touching down on the dusty red planet that once was the epicenter of exotic goods and wares. Now just ruins and corpses litter the red plains, but among the corpses lay endless potential Guardians and one in particular is being searched for by a soon to be endless companion.