I'm game - tell me what else he/she could be? What other category do you have in a comparatively primitive civilised Empire that uses hand-to-hand fighting techniques as standard and the backbone of their armies?
Black
Champion can mean many different things. It can certainly mean a fighter, or someone who bests another physically. "Champion of the Arena" "World heavyweight Champion". But it can also mean someone who stands up for something in a non-martial way. I.E. A champion for equality.
Mother Teresa was called http://www.associatedcontent.com/article/23659/mother_teresa_champion_of_the_poor.html I don't think anyone would say she was a martial combatant.
Ergo, it is concievable that a diplomat who made trade agreements to bring Cyrodil out of a recession or famine could be considered a "Champion of Cyrodil" for his actions. That is just an example, but I hope it illustrates the fact that "Champion" does not implicitly mean "martial combatant".