The Child Thief

Fourteen year old Nick is in trouble. He's on the run from drug dealers with a pack full of stolen meth, and those drug dealers have caught up. He's pretty sure he's going to die. Until Peter shows up. Peter saves his life and promises to take him away to a magical land full of adventure. And Nick follows, through a haunted mist to a strange, magical, dying land full of Devil children, monsters, magic and danger. There he learns he's not been saved so much as recruited, to fight with Peter and his pack of wild, lost children against the Flesh Eaters who are destroying the land of Avalon. As he and the other New Blood find their place in the group, discovering more of the nature of Avalon and of the threat against it, Peter's past is revealed to the reader.

It's basically a grimmer take on the story of Peter Pan, although there's no mention of any of the other characters in the original book by James Barrie.

The Child Thief provides examples of:

 * Action Girl - Sekeu most especially
 * Affably Evil - The Captain
 * Ax Crazy -
 * Badass Boast - The Devils and especially Peter are fond of this
 * Bittersweet Ending - A toss-up between this and Downer Ending:
 * Blood Knight - All the Devils show shades of this
 * Dark and Troubled Past - Peter, and all the Devils... which is why they became Devils in the first place, as Peter purposefully searches out the most poorly treated and lonely children for his army.
 * Downer Ending - Either this or a Bittersweet Ending, depending on how you look at it
 * Hope Spot -
 * Parental Abandonment - Part of Peter's backstory
 * Really Seven Hundred Years Old - All of the original inhabitants of Avalon, and Peter. Some of the Devils, namely Sekeu, might also fit this trope.
 * Self-Made Orphan -
 * "Well Done, Son" Guy - Ulfger
 * What the Hell, Hero? - Nick delivers a couple speeches of this sort to Peter.
 * What the Hell, Hero? - Nick delivers a couple speeches of this sort to Peter.