Bellamy (Bob Morley) and Octavia (Marie Avgeropoulos) always got each other's back, but not in the third season of "The 100."

Based on the latest trailer for "The 100" season 3, a big fight is brewing between the Blake siblings. Octavia is seen beating his brother until he bleeds. Then she tells him, "You are dead to me!"

While the trailer does not reveal any details regarding the cause of the feud of the Blake siblings, "The 100" writer Shawna Benson offered an explanation when fans asked her about Bellamy and Olivia's fate on Tumblr.

According to Benson, fans have all the right to be worried about their favorite siblings on the show. The Blakes are known to be a solid duo, which means seeing Octavia furious with her brother means something went wrong.

Benson also admitted that whatever Bellamy did was meant to protect his people. But she also said that no matter how noble his intentions are, it is more important to know whether he his making the right decisions regarding his actions to protect his people.

"As for Bellamy's choices in Season 3, we'll soon learn not if he's right or wrong, but if he chooses the best option available to him at the time," the writer said.

Meanwhile, an earlier update posted by series executive producer Jason Rothenberg on Twitter revealed that Bellamy will have a highly emotional scene in one of the episodes of "The 100" season 3.

Rothenberg revealed that Morley finished a very difficult scene back in September, and the performance made him cry. The actor replied to his tweet with a joke, asking him if he cried because his act was so horrible.

Another spoiler for the upcoming season of "The 100" came from the show's supervising producer Aaron Ginsburg, saying:

"Don't know what's worse: how much blood is all over set right now or that the blood belongs to a character you guys like... #The100."

"The 100" season 3 is slated to premiere on Thursday, Jan. 21, on The CW.