The Great Heathen Army will be a huge focus on "Vikings" Season 4 when it returns for its 18^th episode next week. Last week's episode formed the army born from revenge and the next episode will take them closer to their enemies' sights.

Episode 18 is titled "Revenge" and features Ragnar's (Travis Fimmel) plan finally coming to "fruition" as the Great Heathen Army "lands on the coast of Northumbria," according to the History Channel. Ivar (Alex Høgh Andersen) and his brothers will set sail to Northumbria and take the battle to King Ecbert (Linus Roache), who was responsible for killing their father, Ragnar, and destroying the Viking village in the past.

Despite the brothers' thirst for vengeance, signs point that they will not immediately launch an attack on King Ecbert, but will deal with the cruel Aelle (Ivan Kaye), the King of Northumbria, first. Episode 19 titled "On the Eve" could showcase Ragnar's sons' force descending on King Aelle, while the 20^th and final Season 4 episode titled "The Reckoning" will serve as the Great Heathen Army bloodshed against King Ecbert.

Northumbria, as expected, will not go down without a fight. According to the synopsis for episode 19, King Ecbert and Prince Aethelwulf (Moe Dunford) will "plan the defense of the realm. In episode 20, Prince Aethelwulf will find himself "subject to the Vikings' battle master plan" and Ecbert "remains behind with a plan of his own."

"Vikings" creator Michael Hirst said in an interview with Entertainment Weekly that Ragnar is still "living in the minds of his sons" after they learned of his death in episode 17. It was evident in how the brothers joined forces to avenge his death. Hirst assured fans that the Great Heathen Army has "got such an amazing payoff in episodes 19 and 20. It's just astonishing."

Meanwhile, Lagertha (Katheryn Winnick) received a prophecy from a seer that her violent death will be in the hands of one of Ragnar's sons. Lagertha became the new queen of Kattegat after killing Aslaug (Alyssa Sutherland). There are strong suspicions that Lagertha's killer will be the ferocious Ivar, given how close he is to his mother, Aslaug, according to Screener TV.

#Vikings - Episode 4.18 - Revenge - Promo, Promotional Photos & Synopsis https://t.co/Rr4BrpkCHy pic.twitter.com/OmEN6vHHHG

— SpoilerTV (@SpoilerTV) January 12, 2017

Watch the promo for "Revenge" below. The episode airs on Wednesday, Jan. 18 at 9PM ET on History Channel.

What do you wish to see in the remaining episodes of "Vikings" Season 4? Who do you think will kill Lagertha? Share your thoughts below!