It's made evident in the first, blood-filled footage from season three, but now Paul Wesley and Joseph Morgan have chimed in and prepared viewers for what's ahead this fall: a seriously dark Stefan.
"We're going to open up with Stefan in the middle of almost losing it," Wesley tells E! News. "And we get to watch the development of that as the season progresses. We see him slowly losing himself... [He's] a freaking nut-bag."
What have Stefan and Klaus been up to? Teases Morgan:
"They've been on a killing binge, quite frankly. Just wreaking havoc... Things are only going to escalate from here, so we're going to see how far these guys are willing to go. And Klaus is willing to go as far as it takes."
He may want to be careful, however: a certain hunter will have this Original in his sights on season three.