A war orphan, he was taken into the house of Mifune Sanjulo, an descendant of a long line of Rocket Knights. There Sparkster was raised as a Rocket Knight himself.
Ten years back, his master Mifune was permanently disabled by the Black Knight Axle Gear.
Sparkster arrived in the Kingdom of Zebulos after searching all over for Axle Gear, upon whom he seeks revenge. He poses as a wandering outlaw, but is in fact a strong defender of justice. He also has a careless side to him and is easily pleased by praise or flattery. "