Kai: Ninja of Fire

Kai: Ninja of Fire is a Ninjago book released in 2011.

Book's official description
''Masters of Spinjitzu: a new force to save the world! ''

 Will Kai be the greatest warrior ever known? Maybe, if he ever listens to Sensei Wu long enough to complete his training! He's stubborn, he's reckless, and he might just save the world.