Millennia ago the Vadrigars has constructed a Temple to connect their Arenas, other planetary Systems, Galaxies, Universes and even Hell.
Being the unique proof of the existence of multiverse, after Vadrigars has disappeared, the Temple is the most powerfull thing to conquest anything in the path of who uses it.
In the past, after Vadrigars discovered that their technology isn't completely controllable, the Temple has builded a Gate to connect Hell, and there they got a war against the Demons, the Vadrigars almost didn't had chance to stop them, but a Demon that have envy of Lucifer, told to Vadrigars how to stop it, then they sealed magically the Hellgate, and maked this demon the guardian of the gate, preventing The First Demon uses it, but that wasn't sufficient.
That Guardian was banned from the Temple after Lucifer has found a way to send his armies to our dimension using another portal that connects indirectly in Hell, only his army can pass, he itself and his generals can only pass to our plan by crossing the Hellgate, that is sealed.
Considering the fact of Vadrigars always choose some kind life to keep the order in the Temple, there is someone in some universe that knows the words to break the seal of Hellgate, and going universe after universe, Hell armies invade and conquest anything that the portals of the temple connects, searching for this words.
A Interstelar Crusader Ship saw this strange event in the Temple and alerted everyone in the Galaxy, now every alien kind solved their differences temporaly to go in the Temple and seal all possible Gates that can be used to connect Hell indirectly, but first they need go Universe after Universe to clean up the dirt that hell armies did on each Universe.
One thing that they doesn't know about, is the magic of auto-build of the Temple, every Universe that is created, the Temple builds automatically a room with many Gates to it.