These forces might look like a colossal beast, yet it got old and weak over time. Not to mention many had their own battles against each other, with deadly wars being ragged all over the universe.
In addition to that, there were tons of forces sent every now and then towards the outside battlefield. Hye wanted to go there, but he didn't have the time nor the power to secure a good spot in such a hectic place.
The outer battlefield was like a massive universe lying between this one and the hostile one. That middle universe was like a flat land, spanning for billions upon billions of miles, stretching without showing an end.
In one part, it got attached to the universe here, and in another part, it ended with the hostile universe. The whole idea of war was to see which universe's forces would span and control most of this universe, securing paths towards the other one, and invade it.