The first thing thing that I want to say about this series is that it's really really good, and easily my favorite fantasy trilogy. That said however the series is also really really
dark. Just for starters it begins with the main character living on the street and instead of going with the normal representation of life on the streets (which is completely ridiculous) the author goes for a much more realistic one. Also the series looks at prostitution, not focusing on it but dealing with the issues of it and the shame that women forced into it have to go through. This series is definitely not for younger readers. However if you can deal with the dark stuff then you will find the series incredibly good.
The main character Kylar is very interesting, a murderer (a Wetboy to be exact, they are basically magical assasins) who yearns for justice. He is very pragmatic which is a nice change from a lot of protagonists. Durzo, Kylar's mentor, is the most Badass
mentor ever but I won't go into that because of spoilers. Logan is a Knight In Shining Armor
who is forced to go through some really bad things but doesn't turn into a Knight In Sour Armor
(not saying that's a bad trope). Elaine is a bit too perfect but she does go through some nice character development. Vi is a badass female Wetboy that is incredibly deep and scarred, struggling to work through the terrible things she has been put through, and my personal favorite character. Momma K is a very strong female character.
The plot is good, the characters are awesome, the setting is nice, the fights are well written, the magic system is a bit unoriginal but still has some new things, and it deals with some very serious issues. I don't know what else to say other than go buy it. Like right now.