Who is The Wendol from Eaters of the Dead: The Manuscript of Ibn Fadlan and what is their importance?

The wendol are mist monsters...... terrible creatures that plague Rothgar's kingdom. The wendols are hairy, smelly, and extremely ferocious, attacking at night when mists cover the land. On several occasions, Ibn Fadlan wonders if they might possibly be human. It isn't, howeverm until they appear in the form of the Korgon dragon that it becomes apparent that they are indeed some sort of men.

When Buliwyf and the warriors confront the monsters in the thunder caves, they find that the wendol are ruled by an old hag surrounded by snakes. The Northmen refer to her as the mother of the wendols, and until she is killed..... the monsters will continue to freely roam throughout Rothgar's kingdom.