The Seer is the religious man of Kattegat. Many vikings visit him to find out about their lives and what the future has is store for them. He is portrayed by actor John Kavanagh.
He is spoken of often as the one who prophesied Ragnar would be the father of many sons.
In both seasons of Vikings he is called upon to translate the wishes of the gods since the vikings believe their futures are already preordained.
(Photo Credit: History Channel, Metro-Goldwyn-Mayer Studios Inc.)