The Adversary is . It's the only explanation.

Some ideas for ya?

"Mister" Dresden
Dresden has now for several years owned a seemingly domesticated male cat.   It should be noted that Dresden's cat "Mister" seems to have odd tastes.  While normally the feline will simply prowl like any other cat.  There has been odd occasions where "Mister" has visited strip clubs.  The cat is larger than most cats and is missing most of its tail.  While attempts to see Mister with the Sight have produced nothing of merit, it is possible Dresden is using the cat in some unknown ritual or spell to fulfill voyeuristic sexual fantasies.  This ceased when Thomas Raith moved in with Dresden and since Raith's departure there has been nothing to suggest Dresden has resumed this pattern.  Shortly before the destruction of the Red Court, Dresden's Chicago apartment was destroyed in a fire.  According to reports from local authorities it is believed to have been arson.  "Mister" is believed to have escaped the apartment but his whereabouts are currently unknown.  However given Dresden's disappearance the cat could be in the care of one of Dresden's contacts or allies.
 

Well if Nemesis is something from the Outsiders then there is a fair chance that Harry and possibly Elaine are both immune or at the very least uncontrolled by the infection as they are Outsider Banes.

thank you for the answers Serack.

I am re-listening to the audio book now that I can focus on the finer details and not wanting to just get to the end .  Very good catch.  I have been waiting for Butcher to bring Tara back into the story.  She was too cool of a character to leave out in the long run.