Fens of the Dead

The Fens of the Dead are a group of small islands in a river delta a short distance south of Paws.

Description
The islands consist almost entirely of noxious marshlands, and are rumored to be haunted by the spirits of deceased seamen and sorcerous liches alike. However, they are also known to house growth of the rare and expensive reagent Mandrake Root. To the west, the delta seamlessly turns into a swamp that makes travel between Paws and Trinsic difficult.

In the time of Ultima VI, the wreck of the frigate Dutchman could be found there, as related in song by the bard Lazeena.

Ultima V: Lazarus
In Ultima V: Lazarus, the Fens were slowly spreading their poisonous influence over Paws. A druid, Windfer, sensed this and asked the Avatar to find the source of the corruption. The Avatar found a Dark Reaper in the fens and killed it, thus ending its influence. Windfer later destroyed the Reaper's heart in order to ensure it wouldn't come back.

Trivia

 * Despite being clearly marked on all maps, some people confused the unnamed islands north of Paws with the Fens of the Dead, most famously the page Mysterious Sosaria.