Where to start? Firstly, did the book work for me? I can answer that with a resounding yes. I loved the slow plot development; there was no real information dump, which can sometimes bog me down, but instead small snippets of information that got me thinking (a lot). This tied in with the almost political-like subterfuge between all of the characters, even those on the same side. It felt like all of the characters were playing a high-stake game of cards and keeping said cards close at hand.
I also loved the slow (over centuries) development of the love/hate relationship between Hugh and Lilith. The heroine (Lilith) was sympathetic, in spite of the fact that she was a demon. She was both true and yet not to her nature. And I liked that my sympathy for her (not that she would have wanted it) was also slow to develop; we didn't discover the reasons behind why she became a demon or her bargain with Lucifer until near the end of the book. I hate being force-fed a character and why I should like her so I'm very grateful that the author didn't do that.
I loved the use of pop culture:
"Do you have your weapon"
"Next to me."
"If anyone but me knocks on the door, use it." Pausing, she reconsidered. After their confrontation in the park, Hugh might seek out the vampire.
"Unless it is He-Who-Shall-Not-Be-Named."
She envisioned his smirk, and wondered how he'd managed to make it through two centuries on a steady diet of pop culture and little else.
"The other one."
Sir Pup waited for her; the odor ofthe park and Hugh lingered on his fur. He glared at her with four eyes, but refused to look at her at all from his middle head. She grinned.
"I meant police officers. You didn't really think he might be harassed by pigs?"
And can I just say I fell completely in love with Sir Pup and spent most of the book on tenterhooks in case something happened to him. Does he re-appear in later books? I hope so! I'm also wondering if the author has a cat as Emilia felt very real.
I did get a little lost at times with the dialogue - I just didn't reach the conclusions that the characters did (about each other and what was occurring) as quickly as they did. That is not a criticism of the author, but one of me. My brain is in slow mode. I think (I hope) that as I continue (because I am planning to read the sequel) that I will grow a little faster at understanding the various nuances, for there are many.
And a special thank you to Katiebabs for suggesting Demon Angel to me in the first place!
Updated to add: If anyone can explain to me how to keep my hard returns in my post I would be very grateful!