03/15/2012 04:46 pm ET Updated Mar 15, 2012

'The Vampire Diaries': Paul Wesley On '1912,' Evil Stefan And The Biggest Shocker Yet

"The Vampire Diaries" returns Thursday night with a flashback episode "1912," and it's going to be quite a game changer.

The episode will not only explain the centuries-long rift between Stefan and Damon, the Salvatore brothers, but it will also reveal the season's biggest mystery: Who's Mystic Falls' creepy serial killer?

"We discover the identity, and it's a pretty shocking moment," Paul Wesley, who plays Stefan, told HuffPost TV in a phone interview.

Could Stefan be returning to his Ripper roots? While Wesley can't confirm nor deny, he does say he wouldn't mind if Ripper Stefan returned.

"I get a little bit jealous that Damon's kind of the bad boy," Wesley confessed. "When Elena picks Damon, it's like, he's so bad, but so good. Meanwhile, Stefan is kind of like the stable, good guy. Personally, I don't like that because I'm not that in real life. But, at the same time, Stefan has proven himself to be pretty erratic. I absolutely went bonkers when I got to play Ripper Stefan. It was like a dream come true to play Stefan as a dark, malicious guy. Saint Stefan can be great, as long as he's flawed. I like when he breaks the rules every once in a while."

In "1912," the love triangle drama takes a back seat to Damon (Ian Somerhalder) and Stefan's brotherly bonding. The Salvatore brothers will share more than a few meaningful conversations across the two time periods. The 1912 flashback will reveal that the two haven't spoken for half a century years -- and it's an understatement to say things are tense. Stefan tries to wean his brother off human blood, but Damon seems to have more of an influence over his younger brother.

As for the present, Damon tries to help Stefan with his control issues, but things take a shocking turn when Damon makes an emotional confession.

"For me, the essence of the show lies in the relationship that Stefan has with Damon," said Wesley. "It's equally as important as the romantic relationships in the show. In the flashback, you get to see Stefan and Damon's relationship in 1912, after not talking for 50 years. Stefan is pursuing Damon's friendship, and in the present day, it's reversed: Damon is the one pursuing Stefan's friendship. They both have resentment toward one another during both time periods."

As for Stefan's relationship with Elena (Nina Dobrev), Wesley doesn't think fans of the couple should give up hope just yet.

"It was an inevitability that Elena would gravitate away from Stefan because of his actions, and it's unfortunate that she had to gravitate toward his brother, but it wasn't unexpected," said Wesley. "It's an ever-shifting relationship, and Stefan and Elena will start sharing a few special moments here and there, which causes her to become incredibly confused as to which one of them is really the one for her -- if either."

"The Vampire Diaries" airs Thursdays at 8 p.m. ET on The CW. Check out photos from Thursday night's all-new episode "1912" below.

"Vampire Diaries" Stills