The long-awaited confrontation between brothers Ragnar and Rollo is finally upon us. The midseason finale of "Vikings" season 4 promises an epic battle between the two brothers, with only one leaving the fight alive.

The previous episode saw Ragnar (Travis Fimmel) finally revealing to his son Bjorn Ironside (Alexander Ludwig) that he doesn't care for Paris. What has pushed the Viking king to return to France was his desire to finish off his brother for betraying him and their people.

Ragnar will finally get his wish in episode 10, but the upcoming confrontation between the two brothers will seal their fates, as only one will be walking away alive. But whatever the outcome is, the victory will be costly.

The trailer for the midseason finale, ominously titled "The Last Ship," gives a hint at how costly the clash between the two cultures will be. The short clip begins with Rollo (Clive Standen) leading his fleet and exhorting his soldiers to "victory or death." The Viking fleet is also shown, followed by a shot of Floki (Gustaf Skarsgard) shouting at Rollo. Bjorn shoots an arrow at his uncle and it hits the post beside Rollo, a clear warning from Ragnar's heir.

The two armies finally clash at sea and there's a montage of the chaotic fight. Viewers can see both the French army and the Vikings boarding individual ships and pressing an attack. Torvi (Georgia Hirst) is also in the thick of battle, fighting the French with her crossbow. Bjorn slashes at his enemies, Halfdan (Jasper Paakkonen) is seen pierced by an arrow and casualties on both sides are shown. Lagertha (Katheryn Winnick) is also seen being stabbed in the shoulder. There's an epic shot of Rollo and Ragnar running toward each other and fighting. The clip ends with Ragnar shouting that "one of us will die today."

It's an open secret that this is Fimmel's last season with the show, as the "Warcraft" star reportedly wants to focus on his Hollywood career. But will Ragnar finally fall in the midseason finale or does he have enough fight left in him to bring down Rollo?

Fans are worried that Ragnar's addiction to Yidu's medicine has weakened him, but he can still surprise his enemies. There's also the chance that Lagertha might become a casualty of the fight. And while there's no question that Ragnar's death will be costly, losing a strong leader and fighter like Lagertha or her son Bjorn will also be a debilitating blow to the Vikings.

The midseason finale of "Vikings" season 4 will be aired on the History channel on Apr. 21.