Rebel Sword — Peter Bostrom

The invasion of the solar system has begun! Private Lucas Walker never thought he'd be a hero. As a grunt in United Federation of Sol's peacekeeper force deployed to Pluto's tiny moon Nyx, the furthest barren hellhole in the solar system, he thought his career was all but over even before it began. He day-dreams of lightsabers, vampires, battlecats, wizards, and all things sci-fi and fantasy while he repairs sand-clogged equipment and mops floors. Then everything changes.  A spatial-temporal vortex opens on Pluto, and out pours an army. A deadly force intent on capturing Earth and enslaving humanity in its quest for universal domination. All universes, all galaxies, all planets--all will kneel and submit to The Dominion. The crap has hit the fan. UFS marines are overwhelmed. The odds look grim. Humanity teeters on the edge. The future of civilization now depends on Private Walker and his ragtag band of misfit UFS peacekeepers, armed only with weapons stolen from the enemy. He needs to figure this hero thing out fast... ...or all is lost.