What sort of ranks exist within the Legion? Are there chaplains who heal their comrades and perform battlefield rights to Arkay? (/whatever Aedra/Dedra the dying person worships.) Or would there simply be priests within the ranks? Obviously there would be commanders, and I have read they had Imperial Knights, but what duties would they fulfill? It seems there was just a LOT of infantry... with a whole lot of not much else in the games, but I am sure there would be more to it than that.
Do you think they would have a separate rank for cavalry, like chevaliers or would just the infantry who were trained to also fight on horseback simply do so when ordered?

I would like to know for a character who's back-story I am trying to develop; a Crusader by classic class definitions and a member of the Imperial Legion who I think would fulfill roles within the legion of not just combat, but healing his comrades on the battle field. Any and all help is appreciated.