Ithguleoir is a mythical creature that lives in the Eltheric Ocean, not far from the coast of High Rock. It is said to be an immortal leviathan that stalks the depths of the ocean, particularly in the waters north of Northpoint and the outer reaches of the Glenumbra Banks. It is described as having an oily back and a demonic stench that smells like it's blown from Oblivion.
The nature of Ithguleoir is largely unknown, but it is known to prey on people that sail in the water. Some have tried to destroy the beast, but none have succeeded. It is theorized that Ithguleoir is responsible for the constant change in the Glenumbra Banks every season. It would fill in the old channels and create new ones, and if a ship was stuck on the shifting sands, then the leviathan would snatch them up.