Vikings season 4: Ivar the Boneless will emerge as a dangerous figure, teases Michael Hirst

King Ecbert is in deep trouble as the great army of Bjorn and Ivar assembles in Vikings season 4 as it inches closer to the finale. The penultimate episode of the fourth season will air on Wednesday, 25 January.

In the previous episode of the historical saga, Bjorn struggles to convince his brothers about his leadership abilities as Ivar the Boneless challenges him. "What battles have you won? What battles have you lost?" queen Lagertha's son Bjorn asks his brother.

The great army later attacks and kills King Aella, who killed Ragnar Lothbrok by dropping him into a snake pit. The sons of the fallen Vikings leader finally avenged the death of their father and are now threatening the kingdom of England.

The official synopsis of episode 19 titled On the Eve reads: The Viking army causes panic in the English countryside as King Ecbert and Aethelwulf plan the defense of the realm. Click here to watch the episode via live stream online.

Ivar, who is battling to find his own place in the politically charged Kattegat, will have to struggle to rise above his step brother Bjorn's reputation. Show creator Michael Hirst teases that Aslaug's son will emerge as a dangerous figure in the future.

"I've always thought of Ivar as someone different from you and me. He just will push things to unendurable levels. He will not recognize normal social interactions or limitations. There is nothing really that prevents Ivar from being Ivar. When Freud talks about ego and stuff, it's like: The ego socializes the id, because the id is just about "Take What You Want." I'm not a Freudian, but Ivar is like the expression of the id unsocialized by the ego, and it makes him a dangerous figure to everyone," he told Entertainment Weekly.

Vikings season 4 airs every Wednesday on History Channel.