Board Thread:Speculation House/@comment-4830106-20151115174306/@comment-14138255-20151122171427

Theory time: Mantle was the aggressor of the Great War, a conflict which required the cooperation of all the nations. Eventually, a coup enacted by Atlas to end the war joined up with the alliance.

OR

Mantle lost and Atlas was given control and they are now in a Weimar Republic/Early Nazi Germany state right now, ready to take revenge.

Either way, they seem to love their military.