New race – Outcasts.

And the justification for the upgrade... So, on Ashan, for every 2-3 meters, there's a warrior eager to "for free" teach a rebel, essentially, how to wield a sword?

Well, I wouldn't say that... Let's say some refugees stumbled upon this house, and then they taught the others, and where does it say it's "for free"?
But the idea is good, it would be better to have one outcast for each of the factions so they don't repeat. Although then you'd have to exclude someone...