The second half of "Vikings" season 4 teases that a new generation of warriors are on the rise. And new set photos hint at it as well.

The History channel's trailer for the latter half of "Vikings" season 4 starts with a strong wind blowing across Kattegat, an apt symbolism that change is literally in the air.

Fans will recall that the midseason finale of season 4 ended with a time jump that introduced Ragnar's (Travis Fimmel) now grown sons and revealed that he had been missing ever since he was defeated by Rollo (Clive Standen). The episode ended with Ragnar's return to Kattegat and the cold reception he received from his people.

In the trailer, the Seer (John Kavanagh) told Bjorn (Alexander Ludwig) that his father's return would bring "calamity, chaos, tragedy, and death," something that series creator Michael Hirst confirmed to The Hollywood Reporter. Hirst explained that Ragnar's return "will cause a lot of tragic and earth shattering events" that really affected the culture of the Vikings and the countries that they raided and settled in.

"This season just propels us into a more universal kind of drama," said Hirst. "What The Seer is talking about really is how huge the impact of Ragnar's reappearance will be on the world at the time."

Ragnar's return will also have a huge impact on his sons, particularly Ivar the Boneless (Alex Hogh Andersen). Fans had already been given a glimpse of the kind of man and warrior the crippled Viking is in the trailer and several Instagram photos reinforce that. Andersen recently shared two behind-the-scenes photos from the set that tease that the rest of the season might prove to be the bloodiest. The first Instagram photo shows the 22-year-old Danish actor covered in blood and mud. He shared another photo the following day that apparently trumps the first one.

Katheryn Winnick also gave fans a look of the goings-on in the show. Unlike Andersen's post, this one has less blood. In the video, Winnick, who plays the badass shield maiden Lagertha, can be seen getting her hair and makeup done. Fans can see Lagertha's braids and what appears to be a crown or hair piece made of leather and metal.

No return date has been set yet, but fans can expect to see Lagertha, Ragnar, and the others when "Vikings" season 4 resumes in the fall.