The Pagan-Asatru band featured is "Wardruna" from Norway, which apparently produced much of the music from the show. This could also foster interest in the pagan music genre as well. Those who will seek out other bands from this multifaceted genre will be surprised at how much is out there.
The spiritual tradition of "the Seer" character is apparently not an Asatruar, but an adherent of "Norse witchcraft." The general theme of Viking paganism was stronger in season three. Floki, in particular, was guiding by the Odinic spiritual tradition... by "the gods." He felt betrayed by Ragnar for his conversion to Christianity. Also, Lagertha's line "If you’ve gone to heaven, then we will never meet again. And yet, I think Odin will ride like the wind and rescue you, and take you to Valhalla where you belong. And there we shall meet again, and fight, and drink, and love one another."
There are many bloggers and forums which have followed the series, such as "Vikings - Fan Site, News and Recaps for History Channel's Vikings." There are numerous sub-plots ready to unfold for season four. Part of what I'm getting at here is that the Vikings were the last great "Heathen Nation" in Europe. This sets it aside from a series about any other post-Roman/Constantine European or Western nation. I know there will be many who will take that first step and google for more information about that "Viking religion." Then the second step, when they type in a search for "Asatru today" or "Odinism modern." Even if one is from a different folk path, it still bridges that disconnect.
I found the character of the Parisian Princess Gisla to be a strong and moving character. During the Viking attack, she stood along the top of the walls of Paris and urged on the defenders of the city. She displayed class and leadership qualities, only to be forced into a marriage with the enemy as it was. That final scene of her standing in her royal clothing and expressing her disgust was one that would get one's attention. If it was shown in a movie theater, dressed in animal furs and with long hair, Rollo's response of saying "hello" in French and then smiling would have received much laughter. Also, of course, the best scene with Ragnar jumping out've the boat/casket! Perhaps his "conversion" was faked?
It probably should be mentioned that--although France had every right to defend itself against the Viking horde--this was only after centuries of extreme Christian aggression against any traditions or ideas which were native to northern Europe.
The "Hexenwolf" legend
Since this posting is Germanic/Heathen in nature, I wanted to add one related article: 'The Legendary Hexenwolf'. This is a part of German-American folklore.
An interesting name
According to IMDb.com, regarding the surname of actor Bob Odenkirk ('Breaking Bad'; 'Better Call Saul'): His last name means "Church of Odin" in Old Norse. It was spelled "Oatencirck" many generations back, and originated with a German immigrant ancestor.
5-11-15 Addition: According to IMDb.com, regarding the given name of the actress Thora Birch ('American Beauty'; 'Ghost World'): Her parents, Jack Birch & Carol Connors, thought that she would be a boy, and planned on naming the child Thor, after the Norse God of Thunder and Lightning. When she was born, however, her parents feminized the name and called her Thora.