While investigating the destruction of several scattered villages, Jack learns that Aku’s new “ultra-bot” assassins are responsible. Unable to destroy them, he hides in the ruins of a village and encounters a mad scientist tricked by Aku into creating the robots. He gives Jack a mechanical arm that grants him the strength to defeat seven of the assassins. When the arm runs out of power, Jack calls upon the spirits of his ancestors to enhance his sword’s strength and destroy the last robot. Aku’s dark energy leaks out of the robots and tries slithering away, but Jack destroys it, causing Aku to remotely feel the pain.