I think the lightning started to tip me off.

do you mean the wife as the connector or the husband as the savant?

No, when Harry talked about tapping into thunderstorms as a way to enhance magic, but also being very dangerous. I think it tipped me off about the bad guy being a novice

still on page 2

I didn't catch on to the lightning stuff for a long time.

about 70% through, but I picked up on that as well, JustJ.

the toad demon fight pretty much spelled it out that the bad wizard was a novice

however, when Morgan suggested it was Harry that pointed to an unknown wizard

when the pizza kid talked about the orgy going on in the house, I was thinking the antagonist had been identified.

I can't comment because I read the book ages ago, so not sure what was memory and what tipped me off....