In the Vikings: Valhalla Netflix spinoff, Jarl Kre claims to have had visions from The Seer, a claim that his Christian friends, including King Olaf, don’t seem to buy. The Seer is the only member of the cast from the first season to appear in Valhalla, although in the form of a long-dead man. The series has always accepted the possibility of the supernatural, with Ragnar even claiming to be an ancestor of the All-Father, Odin. However, it is unclear whether or not Kre’s encounters with The Seer were caused by divine intervention.
Freydis initially encounters The Seer in a dream while she is studying at Uppsala, the hub of pagan Viking civilization. Kre manifests The Seer just before ransacking Uppsala, sharing a similar vision to Freydis. Only Kre claims that his visions continue, telling Olaf about them as they laid siege to Kattegat. The other warriors have brief encounters with the deceased fortune-teller during which they lick The Seer’s palm and inquire about their fate. Olaf and the audience are not shown any proof that Kre’s visions are real, despite his insistence that they are.
The most straightforward explanation for Kre’s visions is that he is insane, driven to delusion by the insufficient information provided to him through prophesy. Kre effectively says so himself, afraid to tell Olaf all about his visions for fear of coming out as insane. Growing up in Uppsala, Kre witnessed the sacrifice of his older brother to the gods, which undoubtedly left a lasting impression on him and served as the impetus for his fervent conversion to Christianity and hatred of pagans. The similarities between Kre’s vision and Freydis’ vision raise the possibility that the Seer is more than just a manifestation of Kre’s guilt.

In Vikings: Valhalla, Freydis and Kre both had visions referring to the prophesy of “The Cross That Carries The Sword,” a title to which both seem to have a claim. The sole vision of Kre that is displayed to the public concludes with him enquiring about his fate, but the response he receives is never really seen. He then quickly destroys Uppsala after that. Kre’s violent outburst and desire to please his God may have been sparked when the Seer claimed that he was not The Cross That Carries The Sword.
The Seer may then have simply been a delusional madman trying to convince himself of a destiny he knew was not his own in every subsequent vision Kre had of him. It’s also possible that Kre misinterpreted the prophecy or that it was intentionally vague so that he could use it as justification for destroying the pagan temple and all of its priests.
It is difficult to determine for definite if Kre (or Freydis, for that matter) actually came into contact with the Seer’s spirit. Despite the numerous unexplainable events that occur in the program, it has never confirmed anything supernatural. The Seer will probably return in Vikings: Valhalla season 2, but it is unclear whether this time it will serve as a literal representation of the gods’ will or serve as a metaphor for destiny.