This book has a great premise, but I was only able to get 40% of the way through the book before I gave up. I believe the author has a great imagination and a strong sense of where s/he wants to go with the story. Unfortunately, I didn't feel like his/her authorship skills are as well developed, to the degree that I gave up on the book.
In the tabletop roleplaying world (Dungeons and Dragons, etc) there's a term for a type of game called "Monty Haul". This is a style of game where low level, undeveloped characters are granted extremely potent items that are way too powerful for them, and the storyline allows them to defeat opponents of a much higher caliber than they honestly have a chance against. This story felt like this type of game. The main character, Landon, discovers upon his death he's an extremely rare type of divine creature, somehow a perfect blend of angelic and demonic lineage. He's absorbed into a supernatural organization dedicated to making sure neither demons nor angels win the war for mankind's souls, thereby guaranteeing mankind maintains it's free will.
Like I mentioned, a great premise. But it falls apart in the execution, immediately and with prejudice. The author clearly believes that the angelic traits are "good", "noble" and "proper" and anything that is tainted by demons is outright evil and chaotic. I didn't appreciate this oversimplistic breakdown. Within a couple of days of our intrepid hero's return to the plane of existence of mankind, he's: met a hooker vampire with a heart of gold, allied himself with an angel (virgin, in a 14yo body - with strong overtones of pedophilia), a "normal" human who's unfazed by learning about the divine world (and is a master fighter), defeats a high ranking demon, learns how to control his powers reasonably well... The list goes on. Painfully.
There is always something happening to the protagonist. I mean, every time he goes out to get something to eat, he gets in a fight or something. Usually, I like fast paced action, but this wasn't "fast paced" as much as "incessantly episodic". Reading this felt like watching someone else play a video game - solve puzzle, defeat boss, get reward, expository cut scene. Over and over again.
The other issue I had with this, and ultimately the reason I finally gave up on it, was the voicing of the characters. They all sound the same. The author tries to mix it up with some different accents or vocabularies, but every character feels like they're being portrayed by the same third tier actor - they show up, they move through the blocking while delivering their lines, and then they exit the stage to make room for the next puzzle/boss fight/reward.
And finally, the auther shies away from strong language, eg "...named after Samuel L. Jackson, motherf**ker." and "...went ape-crap crazy...". Gosh, thanks for saving my virginal eyes from anything that could possibly be offensive in this book that's purportedly about DEMONS! It gets one star for the premise, but sadly that's about the only redeeming factor in this book.