I don't really think any of them have a real arc. No one changes, they just die—and that's totally fine for the story they were trying to tell.
If you throw in "A Fistful of Arrows", you can bookend Jun's role in the games to give him an arc, but that's a) not technically canon, and b) still outside the game itself.
I think the dynamism, such that it is, that comes from Reach's characters is how they react to their situation. Jorge is more than happy to sacrifice himself to save (he believes) his home. Emile ultimately is willing to choose going down fighting over trying to escape. They all ultimately choose a form of sacrifice over self-preservation, and that's the point.