.:Z-Crystals:.

The ancient Guardian fighters who fought and defeated the Shadow King, gathered together and handed down their special powers to others for the war against evil. These fighters placed their powers into entities known as PowerCrystals, so the power could be utilized in the future for other fighters if evil ever returns. Fighters known as "Guardians" were given these PowerCrystals abilities to continue the fight against evils. But Eggman have found out about the PowerCrystals. And want to use them. To bring back the Shadow King.