AJ is Blaze's driver, and is shown to be an expert at driving. While Blaze can drive on his own, AJ usually assists in driving him, often helping him steer in the right direction or stop him by slamming on the brakes. AJ can also operate the major parts of the machines Blaze transforms into.

AJ is an 8-year-old techie who drives monster-truck Blaze, the top racer in Axle City. The two go on adventures that have them taking on problems involving science and math.

Blaze is introduced in Sonic Rush as the imperial princess of the Sol Empire in another dimension, where she acts as a defender of the Sol Emeralds. As her name implies, Blaze's main ability is pyrokinesis; the ability to control fire.