awp832, you are correct that she isn’t a villain character card.
However, she is a character, and she is (one of) Mr. Fixer’s nemeses, as she has the icon.
With Infernal Relics, we will see that nemeses aren’t just found in hero and villain decks . . . but I digress.
The issue here is that The Operative is a Character Card which is not a Villain Character Card, and that creates some confusion - my apologies. I should have more specifically outlined how that works in the Rook City rulebook.
We know she is not a Villain Character Card, as every Villain has the keyword “Villain” right on their card. Citizen Dawn also has the keyword “Citizen” and Grand Warlord Voss has the keyword “Thorathian”, so we know that Villains can have keywords. However, The Operative has the keyword “Assassin” . . . but not “Villain”. She has Character Cards, but not Villain Character Cards. And the fact that she has Mr. Fixer’s nemesis icon does mean something. Whenever he deals damage to her, that damage is increased by 1. Whenever she deals damage to him, that damage is increased by 1.
I hope this helps. Again, my apologies for any confusion.