The main character is a 12 year old boy called Kai Masters and and he lives in a world surrounded by monster-like beasts. A wall surrounds the humans protecting them from the beasts and Kai is one of the security guards on the wall.
"Only a wall lies between the Beasts of Beastium and Earth -and Kai Masters, border guard. When a freaky red tornado hits, Kai knows it's time for battle. Kai chooses his Astro-Jet Striker to battle the wind beast. Can it win over a wind attack?"
Check out this awesome website designed to support the books?