This review is for the full Darkness series - 4 books. Whilst it is a reasonable series, there is not anything new or amazing.
I can't say that I loved any of the characters (maybe West), but most were varied enough to be interesting, although the baddies and comedic sidekicks seemed steriotyped. There was a good use of humour scattered throughout the book and the story flowed well, with action continually keeping the plot moving along. Betrayals and deaths were usually obvious long before they happened, so not too many surprises. There are all sorts of inconsistencies that made me grit my teeth (especially the time difference between human and fae realms. Those changed constantly, even person to person, and made no sense at all. Or that humans could be held captive for weeks, without any food or water - umm, no - you die without water after 3 days). My main pet greve : I often wanted someone to tell Ember to grow up (Lars did... eventually... about three books late). She was an irritating contradiction - strong physically and stoically endured endless forms of pain, but was such a whiny little cow at other times. How many times did she cry that people were not telling her the truth, but repeatedly, when they tried to explain, she would throw a tantrum and flounce off (grrrr). And she ran away so often! Always justifying her actions to herself, but with no thought of the consequences to everyone else. Also, personally, I found it distasteful that such an immature teenager (ok, she was 17 or 18, but she sure didn't act like it) had so many sex scenes. Either make the heroine more of an adult or gloss over the physical side of Ember and Eli's relationship. I skipped most of their nooky episodes as they were freaking me out (seemed like a grown man and jailbait - ewww). The on/off again aspect of their love affair became very tedious.
OK, that sounds mainly negative (sorry). If the above things are not likely to bother you, then you will probably love the series, as Ms Brown does have a very good writing style and interesting world building (time differential aside).