What happened to SB (story)?

[Verdan]

So uhh, the reason why Xenos could kick our butts at the start is because he's a genetic supersolider monstrosity that is being enhanced by an artificial version of the same echo that makes US the main character.

Yeah, but we don't do anything to overcome it, aside from level up; while we use a magic artifact to beat Stockholm Lady. It's confusing.

Another thing that's confusing: the hell are the Garleans doing here? We hear that they've enslaved the populations and we see them get shipped off to be served as not-slaves-but-we-all-know-what's-goin'-on-here, but why did they bother conquering these lands at all? Sure, megalomania and sure, actually having access to captive populations is a vital part of a supremacist civilization, but the empire builds these shockingly massive structures using materials from... where? Wouldn't it have been cooler to see scars where mountains were and giant, industrial pits? Shouldn't there be scars on the land, not just outposts for occupation but a reminder of the industrial consumption of the empire? There's all these fortifications to protect the soldiers, but what are the soldiers protecting? What do the Garleans get out of Doma and Ala Mhigo?