Eggman introduced the new Metal Knuckles to the Grandmasters of the Egg Legion. Later Metal Knuckles fought against Sonic to protect the Death Egg.
Metal Knuckles was assigned to the Echidna Dark Legion and assisted them in their take over of Albion.
Metal Knuckles later attacked Team Fighters on their way to Albion and managed to knock Sonic off the plane, but was the swatted away by Amy. He appeared again to attack Sonic when he was overwhelming Lien-Da and managed to knock him out but was then defeated by Amy.
Metal Knuckles was revived and fused with the Krudzu to become Krudzu Metal Knuckles.