Slag is the leader of the pirates which are seen in Ratchet and Clank Future: Tools of Destruction. He is the one who wants the Lombax Secret for himself. He and his crew were created by Emperor Percival Tachyon but are on different sides due to the fact they both want the Lombax Secret. He has his trusty sidekick Rusty Pete. During the game, he is killed by Ratchet.
He returns in Quest For Booty, after Rusty Pete revives him using his head and the newly possessed Captain Darkwater's body.