Wings of Fire: the Dragonet Prophecy by Tui T. Sutherland

This book starts out like a typical cutesie dragon story.  There are five little dragons representing different elements; a shadow dragon, and water dragon, a sky dragon etc.  They are young, but a prophecy has predicted that they will end a long standing war between their different tribes. For their own safety, they are raised in hiding, but one day they decide to escape and see the world outside.  That is when the story takes a grim turn.  I kind of got the first clue when the first humanoid you meet in the story gets its head bitten off.  From then on the book becomes over-the-top violent.  The dragonets are captured and enlisted in gladiatorial games. One of the dragons shies away from killing his opponent, but another of the cute little dragons snaps her opponent's neck. The startling thing is that some of the dragons, even the young ones, are so callused about killing. Later they come across a battlefield, and the description of the scattered corpses would be rated "R' if they were describing humans instead of dragons.  I really can't recommend this book to anyone within the target age group.  The ladies at the library say it is circulating well.  Sad. (304 p)