The battle between brothers Ragnar and Rollo will come to a head during the midseason finale of "Vikings" airing this Thursday night. The upcoming episode titled "The Last Ship" will have the two brothers face each other at sea — Ragnar with the Vikings and Rollo with the French.

For Rollo, the rivalry with Ragnar is rooted in his desire to step out of the shadows and surpass his brother. This desire led him to Paris where he was able to attain much-desired power after marrying the Emperor's daughter. Meanwhile, Ragnar initially wanted to conquer Paris. Now, however, the only thing he wants to do is to draw a blade through the heart of his treacherous brother.

Based on the promo, the confrontation between these two warring brothers proves to be deadly and intense. As the two finally face each other, it seems that one will be awarded with victory and the other with the kiss of death.

"One of us will die today," Ragnar proclaims in the promo.

Which brother will claim victory in the aftermath of this deadly battle? Will Ragnar have enough strength to endure this waging war?

Even before the premiere of season 4, rumors were already circulating that Ragnar will finally face death this season, especially given his weakened health. Will the battle with Rollo be the final straw?

Although the brothers are finally facing off, viewers shouldn't expect a quick resolution because season 4 is only halfway done. The episode is likely to end with a cliffhanger that will be followed by 10 more episodes later this year. Unfortunately, The History Channel has yet to announce a return date.

To see how the battle wages on, be sure to tune in to "The Last Ship" airing on Apr. 21.

Season 4 of "Vikings" airs every Thursday at 10 p.m. ET on The History Channel.