At the bottom of any wooden sailing-ship, below the crew deck and the cargo hold, there is a dark and horrible place called the Bilge. The Bilge provides ballast, keeping the ship upright. In theory, it is full of water.

In practice, it is full of the most horrible substance ever encountered this side of the Warp itself. Everything drains down to the bilge, and stays there, forever. The water ages over years, filled with dead ship-animals and their droppings, spilled (and eaten, and shat, and re-eaten and re-shat) cargo, stagnating and thickening and continuously roiled and mixed by the rocking of the ship.

Every once in a while, some poor bastard has to go down into the bilge. Sometimes, it's to clear the pipe that leads to the bilge-pump, used to add or remove water when needed (e.g., when the ship takes on or offloads cargo). Sometimes, it's to inspect the interior bottom of the ship for damage, after she scrapes bottom on a shoal or fouls in a shallow channel.

Sometimes, it's to find and kill the thing that's been lurking down there and eating the crew late at night.

One enterprising captain caught upon a solution to the dilemma of whom to order down to the bilge; he got himself a skaven, and had the thing chained in the cargo-deck just above the bilge-hatch. It earned its scraps to eat by clearing the bilge-pump and performing repairs, and after a while its 'fur' - if you could honestly call it that - had become so matted and horrible from the repeated excursions that the Captain found it was punishment enough, to send any misbehaving crewman down to speak to Bilgediver or bring him his bucket of slop.

Recently freed from his captivity after the ethically-challenged sea-captain lost his ship in a drunken gambling bout, Bilgediver has been sold by the ship's new owner to GSM Trust, Inc. (sight - and smell - unseen) for a paltry sum; ostensibly based on his experience with sewer-based work. With the death of Nosecandy Niggler, the management is forced to scrape the bottom of the barrel - literally - for bodies to put on the line of scrimmage.

Bilgediver smells really really bad, even by Skaven standards. He looks even worse, and has developed a permanent sway, owing to years at sea trapped belowdecks. He also refuses to do anything unless first bribed with food, preferably served in a bucket (because a bucket will float in the bilge, keeping its contents (relatively) uncontaminated, at least for a few minutes).