The Vampire Diaries
The Vampire DiariesFacebook/Screenshot

The sixth season of "The Vampire Diaries" has been without a villain up until now but that's all going to change during Thursday's third episode, titled "Welcome to Paradise".

Kai, played by Chris Woods, will be the main antagonist of the season, executive producer Caroline Dries explained to TVLine.

"He is just like a crazy person," Dries said, adding: "[He's] very charismatic and charming and psychotic. Likeable and unlikeable in all the right ways. He's going to stick around for a while."

Elsewhere, viewers will get to see more of Caroline and Enzo bonding in the episode, and Stefan's return to Mystic Falls. Stefan is out for revenge and based on the spoilers, he will have a showdown with Enzo for killing his girlfriend. 

As to what's in store for Damon and Bonnie, spoilers indicate that Bonnie will finally get a glimpse of who is living with them. A promo for the upcoming episode show them discussing the possibility that they might not be alone in the realm they are trapped in.

"No reason to be Peter Pessimist," Bonnie tells Damon. "We have proof we're not alone."

But Damon is far from cooperative: "First of all, don't nickname me. That's my thing," he tells Bonnie. "And this proof is a mysteriously filled in crossword could have very easily been you."

"What are you saying? Are you saying I sleep-crossword?" asks Bonnie, to which Damon replies: "I'm saying it makes more sense than the alternative."

While it's too soon to say who could be trapped with Damon and Bonnie, many have their bets on Lexie. Stefan's best friend was last seen in the season five finale, and many fans believe she could help the two get back to the real world.

Here is what viewers can expect from the third episode of "The Vampire Diaries:

"In an attempt to bring some fun back into their lives, Elena persuades Caroline to meet her at the swimming hole where she plans to introduce her to Liam. Tyler, still working on controlling his anger issues, asks Liv for a favor and is surprised when she makes an unexpected confession.

"Meanwhile, at the lake, Enzo's actions cause Matt to make a startling revelation, and Jeremy makes a discovery about the anti-magic spell that could potentially put Elena's life in danger."

"Welcome to Paradise" will air on 16 October on The CW.