For purposes of my own, I've recently been taking a look at some of these detective stories that I quite honestly despise, especially the ones that make a pun out of something - typically the main character's name - in every title. It blows, and this story was predictably yet another fail, despite the premise being a lot more interesting than most.
I liked the idea of the detective being an excommunicated nun, and her 'Watson' being a demon, but after a short time the story became cloying and one-note. It was too extreme and inauthentic even within the premise we're given. Having written a novel myself which features an incarnate demon, I was hoping this would entertain me, but that hope was dashed with disturbing rapidity.
The novel became annoying, in particular at one point where the inevitable body was inevitably found, and the police were called in, and the detective outright asked the main character if her name, Trixie Lavender, was her stripper name. I'm like "WTF?" I seriously do not get why female writers seem to enjoy going out of their way to marginalize, slut-shame, or otherwise denigrate their female characters, and it was at that point that I quit reading this one. I can't commend a novel that has a female cop gratuitously insult a female witness at a crime scene and there's no pushback from anyone, not even the author.