Also known as the Mechanic, the Water Worker or the Janitor, a traveling handyman who would repair any leaky plumbing if the price is right. Despite his rather bland backstory his actually one of the more mysterious characters in the series. He has been to countless galaxies and knows an incredible amount of stuff. However, he doesent care about evil overlords taking over galaxies and other pointless stuff like that.
The Plumber is one of a few characters to have been seen or mentioned in every game of the Ratchet and Clank series. He usually is shown from behind, working on some piece of faulty equipment. His first appearance was in the original Ratchet and Clank, where he sold the pair an infobot, using the money to escape from the planet of Novalis. He was also involved later on, while trying to repair a gun turret. While this was happening, Ratchet would cover him from incoming missiles, after which he gave Ratchet a metal detector.
In Ratchet and Clank: Going Commando, the Plumber meets up with Ratchet and Clank again at Aranos, where he has been hired to unblock a pipe. A Captain Qwark action figure had been causing the problems, which he removed and sold to them.
He re-appears in Ratchet and Clank: Up Your Arsenal, this time as a waterworker. He offers to pay Ratchet for sewage crystals, as he tries to gather enough to make a necklace for his wife.
Although he doesn't appear on screen in Ratchet: Deadlocked, at the end of the credits it is mentioned that he was unable to appear due to an emergency on a different planet.
He makes appearances in both PSP games in the series, firstly in Ratchet and Clank: Size Matters, though he doesn't speak, and later, in Secret Agent Clank where he can be seen changing the temperature of the prison's showers as they were no longer ice cold.
Ratchet and Clank also run into him in Ratchet and Clank Future: Tools of Destruction, although he does remark "Almost didn't recognise you in High Def". He also gives them a three and three quarter centicubit hexagonal washer, which just happens to be the part that fixes the Dimensionator at the end of the game, allowing Ratchet and Clank to survive.
In the first three Ratchet and Clank games, The Plumber was voiced by Neil Flynn, who also played the part of Skidd McMarxx. In Ratchet and Clank Future: Tools of Destruction however, he was voiced by Jess Harnell.