Citadel of Fire (The Ronin Saga Book 2)

Seventeen-year old Gray is descended from a legendary hero known as a Ronin and haunted by his forgotten past.  He returns home to a wizards' keep, unaware he is now labeled a murderous traitor for killing his best friend.

Now he must cross a dangerous desert full of thieves, mythical beasts, and other magical unknowns, all to return to a home that may be his demise.  At the same time, a poisonous evil seeks to convert the world to their dark mantra, "strength is life, weakness death."