The Seaskulls are one of the three Red groups governing Harbor Bay and they control a sector of the city, including Paltry Place - a harried market, free of Silver overlords.
The Seaskulls are a violent gang, whose business is blood. They are described as being vicious, relentless and stupid, with the "feel of a rabid dog". Members of the Seaskulls are often executed and quickly replaced. The Security officers do not interfere with their business and people part to let them pass. They are often at odds with their rival operation in the city, the Mariners.
Members of the Seaskulls have a tattoo of a white skull of jagged bone, typically on their shave heads.
In 320 NE, when the Mariner Crance and Mare Barrow's group go through Paltry Place, five members of the Seaskulls follow them. They attack and beat up Crance and Shade Barrow for being in their territory, as a crowd gathers around them to cheer. The Seaskulls hope to get a payment from Egan, the leader of the Mariners, in exchange for their return. However, Shade eventually manages to get him and Crance away from them.