EXCLUSIVE: 'Stranger Things' Creators Tease What Fans Can Expect From 'Spookier, Scarier & Bigger' Second Seas

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We're about four months away from season two of Stranger Things!

ET's Leanne Aguilera caught up with some of the masterminds behind the '80s-inspired cult phenomenon at the Netflix FYSee Event in Los Angeles on Tuesday, where they teased what fans can expect when the series returns on Halloween.

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The Duffer Brothers previously confirmed season two would include nine new episodes and four new characters, including Max, portrayed by Sadie Sink, and her brother, Billy, played by Dacre Montgomery. Now, we have a slightly better idea of what their roles will entail.

"[Dacre and Sadie] play these two new characters -- one of them joins a middle school, one of them joins the high school with Nancy [Natalia Dyer] and Jonathan [Charlie Heaton] in Steve Harrington's [Joe Keery's] grade level," executive producer and director Shawn Levy explained. "I'll just say that one of them turns out to be not good news, at all."

"I mean, the [Duffer] Brothers have spoken," he continued. "We've always kinda had that Stephen King kinda model where you have your supernatural threats, but you've got your human threats as well. Dacre's character, Billy, is definitely in that column."

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Matt and Ross Duffer echoed Levy's statements, telling ET that Billy "is a little bit wild," and not someone who appeals to Nancy because "he's more of a sociopath."

"[Billy and Max] come from California, crazy California," the show creators said. "So, they are sort of the big, new teen and big, new younger kid. They sort of shake up those respective worlds when they come in, in various different ways, because they have very different personalities."

"We really wanted a human villain this year," they said of Billy. "We always talk about Stephen King, but he always has… the human villains are often scarier than the monsters, so we wanted to introduce a human character who will scare the crap out of you."

And speaking of supernatural threats, fans are still trying to uncover the mystery of the upside down. Exactly what is this parallel universe, and will viewers get answers? Levy couldn't give us too many secrets (more on that HERE), but he teased just enough info to get us excited.

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"I'm barely going to confirm that there is an upside down in season two -- I will confirm that," Levy dished. "Definitely when you hatch a world like the upside down you're not going to abandon it in future seasons, and there are other threats that make a single Demogorgon look quaint. Just like that."

Levy also told ET that if you thought season one was packed with terror, brace yourselves for even more surprises!

"Let's put it this way, it's definitely spookier, scarier and bigger in its action in spectacle," he revealed. "But I'm also quick to add, because so many people have talked about dark season two, it is still these characters that we love… because we're not Stranger Things if we don't root for these innocent, broken and not quite, you know, fitting into any mold characters. That applies to our kids, who are like magic, and our teenagers, who are trying to find their way."

"So, season two is darker, but season two is very much still about us following this ensemble of characters through their challenges and their lives," he added.

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One character we know will get a little extra onscreen love this season is fan-favorite Eleven, portrayed by Millie Bobby Brown. The Duffer Brothers previously teased that fans will get to hear more about her backstory, hopefully giving us more insight about how she first discovered her telekinetic powers.

"Our goal was to satisfy this profound curiosity about Millie's character and just this female, heroic kind of apparition that the world really embraced, obviously, in season one," Levy revealed. "But we also have to kind of make sure we're not just giving story elements because we think people want them."

"We want to be a satisfying show," he continued. "We're not making the show for ourselves. We're making it for the fans, but it's our instincts that brought us here to this red carpet, so we have to kind of quiet the noise enough to keep hearing and following our own instincts."

The Duffer Brothers chimed in, adding that fans will see a "very different" version of Eleven in terms of "look and personality."

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"I cannot give away too much, but she has a big journey that she goes through this season," they spilled. "A journey of self-discovery for Eleven."

As for Barb?

"Rest in peace," the Duffer Brothers said. "She's dead, if that's what you're asking. But, she's not dead in the mind of many of our characters. So, there's plenty of Barb talk going forward in this season, but we do not see her because she's dead.

Hear more season two teasers in the video below!

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