Meet the 'Dirty Old Bastards' of the 31st Marine Expeditionary Unit as they fight the enemy (and occasionally each other!) in the air, on land, and at sea... Critical Skills Operators one and all, they are the MASTERS OF WAR!

The Speaker receives vital intelligence from a lone Guardian survivor after a failed reconnaissance mission to the Moon. Now he must revive a fireteam composed of a psychotic warlock, a berserker titan, and an outlaw hunter. Will FIRETEAM OBSIDIAN be an asset to The Last City? Or will they be its annihilation...