They came out of nowhere.  Swarms of creatures that could fill entire star systems with their numbers. They fed off everything living and would eat metal to enhance themselves.  The swarms had different appearances, but they usually seemed to look like some monstrous combination of insects, lizards, and mammals. We, the Federation of Terrans, were the first to be hit. Within months dozens of colony worlds, outposts, and space stations were lost. When the first fleets were sent out to find and solve the problem, the starships that returned could be counted on one hand.  Soon after, the Crimson Monarchs and Silver Empire found their border worlds under attack.  The threat was universal. It quickly became apparent none could ignore it. The Federation was pulled from its constant internal strife, and the Silver Empire and Crimson Monarchs halted their war for the first time in over three thousand years.  A coalition was formed, and over the last few centuries, we drove The Swarms back to their home.  But when we arrived, there was no world. Only a crack in our dimension.  If we ever wanted to end this war, our only choice was to dive into the breach.