The effect of the Great Rings upon Men

[Zigûr]

Originally Posted by Ivriniel

Then pondering the Will-Undead, there were also the Wights of the Barrow Downs, who were created, I thought, by Angmar and a part of the reason Arnor failed. The occupation of the Burial Mounds of Arnor were violated by Undead presence which somehow caused the realm to fail... Necromantic Undead Will, even in burial mounds had some pervasive influence on Arnor's strength.

This relates back to the idea of Elves and Fading, as it is suggested in Morgoth's Ring that Undead in Middle-earth (like the Barrow-wights) tend to be "Houseless": Elvish fëa which have refused the call to Mandos and haunt Middle-earth.