The Isle of the Dead is a tall, rocky spire located just to the west of Blood Lily Island. It is the most western point in Deltora. There is a cave near the peak of the Isle that has almost always served as a den for Kobbs. The surface of the isle is covered in hardened Kobb slime, making it shiny and glassy.
Doran described the Isle of the Dead in his travel guide Secrets of Deltora. He noted that one should not visit the isle because of the dangerous Kobb. Many Jalis knights and Diamond dragons tried to rid the isle of the Kobb but when one was killed, a new one would take its place. According to Doran the isle serves as a fine habitat for Kobbs.
The Isle of the Dead was the hiding place of the third sister, the sister of the west. In the time of King Lucan, Doran set out on his last expedition to save the remaining Deltoran dragons. During Doran's expedition the Four Sisters were put into their place.
After Lief had reclaimed Deltora and freed the slaves, he and his companions set out on a journey to destroy the Four Sisters. Lief, Barda and Jasmine travelled to the Isle of the Dead in search of the third sister. After the Sister had been destroyed, the Kobb reclaimed the cavern. The waters around the Isle are very rough and turbulent, making them dangerous for ships.