Apparently this being is one that the All-Father himself had sealed away. His presence sows doubt and fear into the minds of his victims, weakening their resolve and weakening them to his army's advances. I don't know how much power he wields, but it must be great to send Odin into hiding, don't you think?
Well of course you would think so, just this once I agree. When it comes to matters like this, you deserve a warning.