think I've answered my own question:
from the category descriptor posted by tricia earlier:
Rewards a special character from stories which strongly highlight a supporting character from the series or creates a new, interesting character that plays an important role in the story.
'strongly highlights' - I assume that means the character gets a lot of 'screen time' but is not necessarily the main character or characters (L & C) This does not preclude the character being the central character, of course, but s/he's more likely dr watson or moriarty rather than Holmes , given how our fanfic goes.
'plays an important role' - so could be either a saint or a sinner
c. (who has likely got it all wrong)
