"Vikings" season 4 promises major changes in the characters' lives, and not all of them are for the best.

Rollo's (Clive Standen) decision to betray his brother Ragnar (Travis Fimmel) has far reaching consequences and one that he knows he will be answering for. But there are more immediate problems at hand as his new wife is not happy with being forced to marry him.

A recently released sneak peek into Rollo and the Princess of Frankia's wedding night shows things are not off to a good start in this match. The clip shows Gisla (Morgane Polanski) crying as her husband strips down to his trousers. The princess starts praying as she retreats to her bed but shows some spunk when Rollo approaches her.

Rollo tells her not to be afraid as she is now his wife. But Gisla, who's more angry than frightened, quickly pulls out a knife. Unfortunately, her husband seems to find her holding a knife to his throat amusing and quickly disarms her before telling her good night.

While Rollo was quick to dismiss his wife as a threat, she might prove to be his undoing in the end. The princess has made no secret of her disdain for the marriage and might be willing to do anything to rid herself of it, even to the extent of betraying him to Ragnar, as the IB Times suggested.

Princess Gisla is just one of a number of new characters that "Vikings" fans will see this season. Show creator Michael Hirst revealed to The Hollywood Reporter that the latest season will also introduce King Harold Finehair (Peter Franzen) and Halfdan the Black (Jasper Paakkonen), two Viking brothers who will go with Ragnar to Paris.

Katheryn Winnick, who plays the shield-maiden Lagertha, also talked about her excitement about the new characters. In a video interview for the History Channel, the 38-year-old actress said the new faces "brings a different energy on set, and it changes the show," bringing it to whole new level.

"Vikings" season 4 premiere episode, "A Good Treason," will be aired on Feb.18 on the History Channel.