After a strong start, I was delighted to feel a little sympathy for the devil, revelling in a prodigal use of magic, the temptations and the promise of learning a new magical craft, but soon after, I wondered why we were stuck in the house... 
 And then the book turned into a murder mystery! Oh! Fallen angels and the Jade Emperor and even more all mixed into a multiple mythos pot and we've got rivalries between the houses becoming more and more prominent. 
 All well and good. Sort of. 
 The problem I ran into, almost immediately, was neither the premise nor the setting or even the tension. There was plenty of action and things moved out of the house and into Paris. Yeah! Cool, right? 
 No, the problem was the characters. None of them managed to really stand out except by nature of the baggage that comes along with them. Morning Star? Okay, no baggage there. Even that wouldn't have been a big problem had all the fallen angels had a bit more grit, depth, and creative differentiation between them. What happened to Morning Star, himself, felt like a huge letdown. Immortals, Semi-Immortals, and Mortals using magic is all well and good, but when you start blurring the lines without extremely good and interesting reasons, it kinda loses tension for me and then I just started wondering if there was any reason for it all. 
 Why fight for the honour or survival of the houses? I lost interest. 
 Unfortunately, I liked how it began and I was invested in the characters. I realized rather quickly that this was mainly a character-driven novel, so the strengths should have been focused there or at least in some rather more interesting events that helped put the characters in the types of conflicts that aren't just blood and guts but also develops their character. It's not that much to ask for, is it? 
 Even the climax, however overtly interesting and full of intrigue, predicated upon being invested in either the House or in the MCs. Maybe it's just me, but I just wasn't all that invested. I really wanted to like the novel from the initial promise. 
 There's a lot of ways it could have gone, but instead we've got a bunch of normal folk (who happen to be magical fighters, fallen angels, or in communion with the dead, when they're not hiding behind the walls of their fortresses). Like I said, the premise was promising. Maybe a firmer grounding in Paris, full of better immersion, could have saved the characters. Perhaps a few stronger plot-lines and deeper exploration of one or two of the hearts of the minor characters. I don't know. I just wanted a lot more than just talking and explaining interspersed between admittedly cool magic and otherwise forgettable action scenes. 
 It just didn't stand out that much by the end, but it wasn't as if it was an incompetent novel. It wasn't completely unentertaining. The main twist was okay, but the novel obviously feels like a setup for a very long series that's still holding its cards close to its chest. 
 I'm not certain I'm interested enough to continue, unfortunately.