Fanon

"That's not canon!" "I don't care! It's my fanon!"

In this way, smaller groups within a fandom agree on readings which may be completely at odds with the canon, but which in time acquire legitimacy as fanon.

Loyalty is one aspect of Slytherin that canon and fanon readings technically agree on, but fans are significantly more sincere about this characterization.

So in a fandom as old as Austen's, how does fanon get created?