Redoubted Island

An island inhabited by a giant.

During inclement weather, the giant lit fires on the island to attract passing ships in need of a port. When the ships arrived, the giant would kill everyone aboard. The giant was eventually killed by Uther Pendragon.

Much later, King Mark of Cornwall, after Tristan’s death, was deposed and exiled to the Redoubted Island. However, he eventually escaped and reclaimed his kingdom.