Sunday afternoon, the creators of ABC’s “Once Upon a Time” visited Anaheim to take part in WonderCon 2012. Adam Horowitz and Edward Kitsis headlined a panel where they debuted tonight’s episode “Heart of Darkness” hours before its premiere. The pair also gave attendees an inside scoop on the spring finale and revealed one character’s big return. After the screening, audience members got to ask some important questions. Who is Dr. Whale in fairy tale land? And what other fable characters will appear on the show?

Find out more in our “Once Upon a Time” breakdown…

Guess who’s back?

The producers came to WonderCon with big news. A certain dead and scruffy male star is back from the grave. Jamie Dornan aka the Huntsman aka the hipster sheriff, will (once again) grace us with his presence. Kitsis proclaimed, “The Huntsman will be back for the finale. And I have to warn all of you he’s grown more handsome.”

What’s up with August?

Over the past few episodes, August has made his presence known. But aside from his name, and his meddling with Henry’s book, we know nothing about him. According to Kitsis, by the end of the season we’ll know who August is and why he’s in Storybrooke. A small bit of his agenda is revealed in “Heart of Darkness.” Pay close attention to a conversation he has with Henry at Granny’s diner. He’s a man on a mission.

Dr. Whale’s secret identity

One character who’ll stay a mystery a little longer is Dr. Whale (David Anders). Horowitz and Kitsis won’t be revealing his fairy tale roots this season. But they urge fans to be patient because they “have a plan.”

Characters on Horowitz and Kitsis’ wishlist

We’ve seen lots of famous characters appear on “Once Upon a Time.” They’ve done Snow White, Cinderella, Little Red Riding Hood, Hansel and Gretel and many more. So who will they tackle next? The producers confessed that they’re desperately trying to get their hands on Peter Pan. They’d love to do Ariel from The Little Mermaid, Rapunzel, and Mulan is also a favorite.

More “Lost” stars

Earlier this season, Emilie de Ravin and Alan Dale guest starred on the show. Dale starred as King George and de Ravin as Belle from Beauty and the Beast. Both actors are best known for their previous roles on Lost as Charles Widmore and Claire Littleton.  Horowitz and Kitsis said, if the opportunity presents itself and the story’s good they’d love to work with more actors from their alma mater.

“Once Upon a Time” airs Sundays at 8 p.m. on ABC.