Grasp of the Empire

At the center of worst Dark Age in history, mankind after the expansion across hundreds of star systems have been left defenseless while rivers of blood cast them from all directions. This brutal Empire that enslaved the entire race is falling apart from inside civil wars. With all of that going on, an outside threat was crawling through this nation as a dark cancer ripping apart the entire civilization, destroying everything on its path. This dark force appeared with an amount of rage and monstrosity far beyond any man can comprehend. This wasn't a matter of defeat or victory, but a matter of how long can these kids survive this? How long can they deny that something huge is about to happen?