This is the penultimate chapter. All must be revealed here, because the next chapter is only going to be denouement. So, we learn, alas, that Edward is, in fact, the big bad. But, as Connie says:
I was realizing that Edward was kind of pathetic, as bad guys went. He wasn't even really evil, not in a stylish Hannibal Lecter sort of way. He was just...a dickhead. And a dumbass. The problem was, he was also controlling an incubus.Indeed.
So, Connie manages to get the upper hand, and she vanquishes the incubus, and, in the end, it's kinda anti-climactic. I mean, it's what you would expect - there isn't much point to getting this far and having Connie fail to vanquish the demon, but I'd kinda like the fight to have been a bit more drawn out. Except, that might have turned Connie into a "spinny killbot" (to totally steal Scalzi's neologism) instead of portraying her as an actual human girl type character? It's not like she's been presented as some sort of martial artist up to this point; it would be wrong to have her turn into Buffy all of a sudden. She does rough up Edward a bit, physically and emotionally. Perhaps there could have been some reference to soccer here - she could have kicked the demon in the shins or something? I don't know.
Here's what I hope for from Chapter 30. I hope for some glimmer of a sequel. If this can be the "first fight, dear deity, how did I win that, knowing what I know now" sort of character back story, I think this fight scene works. But as the culmination and termination of a character arc, it's kinda lacking...