It makes no since to have a priest as a marshal. I mean Priest can control a army but to control the army on the field does not make any since.
You would need a damn good vice marshal
I did this for a very short time in Solaria, until we were able to find someone to take up being marshal. Made for some great RP's of me blessing the army before battle etc, but from purely game mechanic perspectives, my character added little to the army, no unit and not able to lead the combat.
