The strained relationship between Elijah and Klaus will set off a chain of events when "The Originals" returns to The CW with Season 3 next fall.

During the "The Originals" Season 2 finale, Klaus cast a spell on the mother of his child, Hayley, in order to win Dahlia's trust before defeating her. Because of the curse, Hayley will now be forced to live in wolf form except for on the rare occasion that there is a full moon, which occurs once a month.

Although Klaus' plan of deception helped him send his evil aunt to the underworld, Elijah will be furious that his brother cast a spell on the woman that he loves. As a result, their brotherly feud will become more intense.

"I think the rift between them is going to precipitate the chain of events," said series star Daniel Gillies, who plays Elijah, during an interview with The Wrap's "Drinking with the Stars."

"It's not just a begrudging alliance now -- it's an alliance on its last thread of trust," he added.

He went on to say that the brothers will not patch up their relationship anytime soon as their bitter conflict is "the fundamental problem of the entire show."

Executive producer Michael Narducci also dropped spoilers about the upcoming season, telling TVLine that the biggest threat in Season 3 is going to be Davina Claire now that she has been appointed as regent of the witches of New Orleans.

"The spirits are going to have access to Davina," teased the EP. "They're going to lend her their power and communicate with her about what's best for the people and witches of New Orleans. That's who she'll be an advocate for, and the Mikaelsons, some would argue, are not the best things in the world for the witches. That's going to put them at odds, assuming there's no larger threat coming for which they might have to unite against. There are a lot of different ways this could play out."

Watch Gillies' interview with The Wrap below.