Continuity/Undead

An early version of the Zone Bestiary had a very different back-story on the existence of undead from what is known now. It stated that, "Undead [are] mostly the risen forms of those who died before discovering the Lifestones. Some evil magic, its source unknown, is touching the slain and raising them to wreak vengeance upon the living," and gave two possible explanations: one, that according to Sho tradition magicians who bargained with demons sometimes rose after death and two, that Ardivan Locke interrogated a Lich and concluded that undead housed evil spirits, possibly related to the powers Bael'Zharon.

There was a lot of early content designed around this idea. Undead Humans exist in places like the Colier Mine, Mines of Despair, Mount Lethe Magma Tubes, and others. Other locations had Undead and Shadows together or Undead with an Altar of Bael'Zharon, like in the Sylsfear Dungeon, the Lost Garden Ruins, Mount Lethe Magma Tubes, and Old Talisman.

Early in the The Fourth Sending of Darkness the current back-story for undead appeared. This version states that many undead are actually Empyreans from the ancient kingdom of Dericost and that they became undead using the Blood Magic they learned from the Falatacot. Some attempts were also made to retcon some of the earlier examples of undead. Some undead, it was said, were the results of Lifestones not functioning properly. When Lifestones first began to appear, they would reanimate the corpse of the fallen Isparian rather than resurrect them fully healed.

Conclusion

The Dericost/Blood Magic explanation was a retcon of the previous story, and is considered accurate. Attempts were even made at explaining some of the out of place undead. In her letter, Aerfalle wrote to Rytheran, "You know as well as I the reanimated make poorer servants than the converted." While this was in reference to Yalaini who had died in a volcanic eruption, the principle behind it helps explain the various Isparians who were said to have fallen and been ressurected by liches. The letter went on to explain how some undead (called firstborn in the text) had sworn to serve the Hopeslayer, "for no greater reason than that the Servant was raised near Daralet." and went on to site the Sylsfear Dungeon (called Old Fauzuil's retreat in the text) as an example of undead and shadow in the same location.

Still - there are some cases where the early back story is the only reasonable explanation, such as the with the Undead Isparians of the Mount Lethe Magma Tubes, or those in the Dungeon Mei. And more recent content has introduced more possible ways for a creature to become undead, such as with the undead Rushck of the Dark Isle who appear to be the result of Grael's magic, or the undead of the Ancient Graveyard who were cursed with the magic from the Book of Eibhil.