It didn't seem to go too badly for the Muslims when they conquered and held it for about a thousand years, and the Europeans when they set up colonies for a few hundred years, only to have them fall apart because the home countries were crumbling from within after devastating wars and could no longer afford to project their influence... I mean, by the standard that things went badly for any of those players, you might as well say everything is doomed to end at some point.
It didn't seem to go too badly for the Muslims when they conquered and held it for about a thousand years, and the Europeans when they set up colonies for a few hundred years, only to have them fall apart because the home countries were crumbling from within after devastating wars and could no longer afford to project their influence... I mean, by the standard that things went badly for any of those players, you might as well say everything is doomed to end at some point.
That was easy for them since most of their "home" territory is just close to it. While the Europeans had to cross a sea to reinforce their forces. Besides that is how the Axis lost (along with Hitler's meddling)
This "Empire" of Youjo Senki is a piratecopy of the Second Reich, not the Third Reich and in the end (chapter 9 of the manga and end of volume 1 of the light novel), the Empire shared the fate of it's OTL counterpart: Defeat and post-war chaos, but since the characters in that scene were talking just about "the World War" instead of "World War One" and "World War Two", we can assume, that the post-war chaos was less severe or was handled differently in some way, so that world had the joy of being spared of the existence of a Third Reich counterpart altogether.