Season 4 of "Vikings" left a lot of intense cliffhangers stemming from the deaths of significant characters. With Ragnar Lothbrok (Travis Fimmel) no longer in the picture, "Vikings" season 5 is expected to focus on his sons as they rise up the ranks. However, conflict continues to heat up between the brothers as each proves himself worthy to carry on Ragnar's legacy.

In the "Vikings" season 4, Ivar the Boneless (Alex Høgh Andersen) emerged as the black sheep of the family, killing his brother Sigurd (David Lindstrom) in a fit of rage. Speaking to Variety, "Vikings" creator Michael Hirst revealed that the fifth season will begin with Sigurd's burial, during which Ivar is weeping and saying that he never meant to kill his own brother.

Sigurd's death deals a heavy blow to the family and ultimately tears them apart. "They split up into different camps. A large part of the next season will be about, will it be like this great Roman conflict after Caesar's death, the great Roman civil wars with Brutus and Cassius and Octavian?" Hirst explained.

There's a theory, however, suggesting that Sigurd is not really dead. Some fans believe that after Ivar lodged an ax in Sigurd's abdomen, he did not really die and was only left unconscious by the river bank. Viewers also noted that the ax Ivar used was too small to inflict a fatal blow.

The argument finds its roots in history, where it is said that Sigurd lived a longer, more prolific life than that depicted on the show. As a matter of fact, Sigurd married Blaeja, daughter of King Aelle of Northumbria. Their union was controversial because King Aelle was the one who threw Ragnar into a pit of snakes to die.

"Vikings" theorists believe that Blaeja may have found Sigurd and rescued him before his brothers could retrieve his body.

Meanwhile, Jonathan Rhys Meyers is going to be introduced as a key player in "Vikings" Season 5, where he's playing Bishop Heahmund. "If he doesn't perform the duties that he's meant to perform, the story won't move the way that it's meant to move," Meyers told Collider about his role.

"Vikings" season 5 is expected to premiere in fall.