I dunno, I just had a thought after seeing a cosplay of a Spartan, who didn't have a helmet on. I was thinking, "Hey, that girl looks pretty cute, and young. The suit didn't really seem to FIT how young and innocent she appeared." and then i was like- wait. Spartans ARE young, and maybe not innocent, but all they've ever known and remembered was war, war, war. Maybe this alt-universe version of them, the psuedo-UNSC was replaced by a more civilian organization, to demilitarize and then humanize the war-torn cities and planets that had been long since converted into military strongholds and outposts. And in their infinite wisdom, they didn't see the psuedo-SPARTANs as genetically engineered war machines, but rather as children who had simply been blown off their path. And so, they reward them for their service, with all the awards and benefits becoming of supersoldiers who won the hundred-year-war, and set them into the world, with classes to educate them on more civilian matters, and mentors for each of them to acquaint the teenagers- however large and matured they are- of things more 'befitting' their age.
And so the entire roleplay would be about supersoldiers trying to fit in, when all they know and prefer is fighting.