Vikings season 4 has reached its midseason finale and fans of the historical drama are eagerly waiting for the battle between the Norse brothers — King Ragnar Lothbrok and his younger brother Rollo.

In a promo released by History Channel, the king of Kattegat confessed that he declared war not to fight with Paris but to kill his brother, who went rouge and backstabbed him by killing his own Viking fellows and fighting for King Charles.

Click here to watch the episode via live stream online on History Channel.

"Victory or death," says Rollo as he marches towards Bjorn and his father's army. But before coming face to face with the Norse king, he has to face Bjorn and Floki, who have blood in their eyes to take down the treacherous brother of Ragnar. By the end of the episode, it will be revealed which Lothbrok brother will make it alive.

But they are not the only one to have the sword of death hanging over them. The promo for episode 10 reveals a shocking scene during ferocious fights and it appears Lagertha's life might be in danger.

Lagertha suffers a miscarriage in the previous episode and is devastated, even though she admits she knew she could never have a child. And her mental state might reflect in her fight.

The synopsis of episode 10 titled The Last Ship reads:

A ferocious battle between the Vikings and the French eventually comes down to Ragnar against Rollo and the outcome seals the fates of the two brothers.

As of now Bjorn looks safe, compared to his ailing father. Torvi killed Erlendur using his crossbow in a bid to save the life of the future king of Kattegat. Ecbert, meanwhile, has been crowned as the King of Wessex and Mercia leaving King Aelle feeling betrayed.

It will be interesting to see how the characters take their final move in the midseason finale episode of Vikings season 4, which will air on Thursday (21 April) on History Channel.