I thought we were pretty much fine with Marqs description
"champion of good from either a narrative or an in-universe POV, whether or not they're actually The Leader
of the good faction(s)"
maybe add in that they're typically the driving force of the plot either by being The Face
, The Chosen One
or having It's Personal
motivations for the main conflict. Basically that they are The Champion
for the plot as a whole.