'Vikings' Season 4 Air Date, Cast, News & Update: Is Season 4 Ragnar's Last? New Season Belongs To Lagertha, Rollo's Betrayal Inevitable [Spoilers]

History Channel's "Vikings Season 4" will leave France and the Siege of Paris behind and see Ragnar Lothbrok (Travis Fimmel) back home in Kattegat. Fans are anxious to know what state Ragnar would be in when "Vikings Season 4" premieres. With Ragnar's impending death, Ragnar's first wife Lagertha (Katheryn Winnick), son Bjorn Lothbrok (Alexander Ludwig) and Princess Aslug (Alyssa Sutherland) will vie to take to the forefront in their bid for the throne.

Starcasm reports that when "Vikings Season 4" opens, two years would have passed from the "Vikings Season 3" finale. As confirmed by "Vikings" creator Michael Hirst, who also created "Penny Dreadful" star Eva Green's "Camelot," Ragnar's trip home would have taken around a couple of years under difficult conditions.

This corroborates Hirst's description to Hollywood Reporter of Ragnar's state in "Vikings Season 4." "It's very important to note that he's not only sick; he's hovering between life and death," Hirst stressed. "So that impacts hugely on the beginning of season four, which we're working on now. It's a big story point. It's very important that Ragnar is weakened, ill and hovering between life and death when we come back for season four."

Rollo, new husband to French princess Gisla (Morgane Polanski), will yet again be on the path of betrayal against Ragnar. If brother against brother will come to the forefront in the face of the undeniable offer by the French to Rollo, "Vikings Season 4" will soon tell. However, Rollo's is not the only relationship that fans wonder about given the sentiments Ragnar overheard when Floki (Gustaf Skarsgård) and Lagertha thought Ragnar was already dead during Season 3's finale.

Still, the premiere episode for "Vikings Season 4" called "A Good Treason" is a teaser all its own. Carter Matt reports Lagertha will showcase her mettle in Season 4 even while Princess Aslaug and Bjorn Lothbrok plot to win Ragnar's throne.

"In the Season 4 premiere, a dangerously ill Ragnar returns to Kattegat, where his suspected death kicks off a scramble to succeed him," Carter Matt stated. "Meanwhile, Lagertha engages in a power struggle with her calculating, former second in command, Kalf; Rollo betrays his heritage and remains in Frankia; and Floki pays the price for his brutality against the Christian priest."

Harold Finehair (played by "True Blood" actor Peter Franzen), Halfdan the Black (Jasper Pääkkönen) and Yidu ("Descendants" actress Diane Doan) will make their way into History's hit series come "Vikings Season 4." The new season will premiere on February 18 at 10pm ET on The History Channel.