That the writers managed to put both "Blood Eagle" and the final episode, "The Lord's Prayer"-- and Ragnar's farewell soliloquy to his dead daughter, Gyda -- in the same season puts Vikings at a level that other series don't reach, at least series that are historical entertainments staged against gorgeous scenery, with period sorts of battles and other violence. For these people the gods matter, and we, as viewers, enter into that world view with the characters.
The choreography is brilliantly staged for the scenes in which King Horik is irreversibly trapped. Over a series of beats, one-by-one his fine plans to wipe out Ragnar, all of Ragnar's family and supporters visibly drain out of his face. At the same time, one-by-one, the principal figures Horik had slotted for destruction walk out of Horik's cage. They depart the scene in different directions: stage right, stage left, upstage, downstage.
All of them knew he'd cold-bloodedly planned to kill them all, after having suborned them into betraying Ragnar, out of nothing more than jealousy of Ragnar. They all know all this, and he knows they know it. They turn their backs and dismiss him. This lifted the scale of Horik's end to the level of tragedy. The scene could have taken place in an amphitheater of ancient Greece or London's Globe Theater, or in Joe Papp's Public Theater.
Or -- does the tragedy really belong to Ragnar, and his choice, his privilege to beat Horik to death, breaking his face into blood, bone and brain fragments with his own skull in a berserk passion of hatred for what Horik had tried to do him and his family?
How could Horik have ever thought he'd successfully betray and beat a man like Ragnar, whom he watched with his own eyes, execute another man who stolen what his, executed Jarl Borg by the blood eagle, and did it himself, not by a priestly intermediary? A man with that strength of mind cannot be defeated.
Yet, when Horik requests that his son be spared from the general execution of his family, Ragnar does spare Erlendur, even though Horik ordered all of Ragnar's children be slain, and particularly his oldest son -- to be accomplished by the hand of of one of Ragnar's own people, he'd arrogantly believed he'd recruited with lies so transparent any woman could see through them. Ragnar, why kill all of Horik's girl children and yet keep alive the eldest, the son, who already is of fighting age? That's a weed, which within dramatic entertainment convention, is likely to strangle Ragnar. Maybe that's another aspect of the tragedy, the tragedy that isn't Horik's at all -- but Ragnar's own.
Have we ever seen this done on a television entertainment series before?
This was worthy of the works, the legendary personages and the events, that inspired the eddas, chronicles, histories, sagas and epics on which Vikings is based.