When "Once Upon a Time" returns, an evil character will be making a comeback. TVLine reports that Rose McGowan will reprise the role of young Cora in Episode 18. 

McGowan first appeared as Cora in the March 2013 episode titled "The Miller's Daughter." In the episode, it was shown through a flashback that Cora and Rumple were once romantically involved. That is, until Cora removed her heart to pursue power as Prince Henry's wife. By episode end, she had given birth to baby Regina. 

Cora is expected to add to the show's complicated family tree, which will add two new branches by the end of the season. 

The series is also casting the one-episode role of ruthless pirate Blackbeard. 

Series co-creator Adam Horowitz also said that the fourth episode back, called "It's Not Easy Being Green,' will shed light on the Wicked Witch, as well as her issue with the Evil Queen. "She's got a whole backstory and mythology," Horowitz said. "We used the original [L. Frank Baum] book as a jumping-off point, and then spun her in a hopefully unique, Once Upon a Time way."

He added that when the Wicked Witch meets with the Evil Queen, "There are sparks that fly."

Also, when the show returns, it will be apparent that the destruction of Storybrooke did not reverse anyone death's--except maybe one.

One death may have been undone due to the burning of the Shadow. (Big hint: Co-creator Edward Kitsis said Rumplestilskin definitely died, but he's "the Dark One," meaning he may not stay dead.)

When viewers last tuned in to the series, Peter Pan (Robbie Kay) attempted to reuse Regina's (Lana Parrilla) curse, which forced everyone back into the Enchanted Forest and destroyed Storybrooke. But Emma (Jennifer Morrison) and Henry (Jared Gilmore) were not part of the original curse, so their memories were wiped clean and they stayed in the mortal world. Now they are living in New York City, leading quiet, normal lives. That is, until Hook (Colin O'Donoghue) showed up to tell Emma that her parents are in trouble. 

Hook now has to make Emma remember her fairytale past. 

Horowitz said Emma will have two sets of memories. "The ramifications of this new life of Emma's that we glimpsed at the end of the winter finale and what would happen if she did regain her memories play a huge part in the second half of the season," he said. 

He said that the new Emma will be a bit different, but with similar personality traits. "She has some new memories, but that didn't ruin her upbringing," he explained. "She still grew up tough, she still grew up with a wall. It was her against the world and what we'll see is with these new memories it's now her and Henry against the world. She still is the same person, but we're going to really explore what her life is like in Episode 12 called "New York City Serenade.""

Although Emma's memory was wiped clean, the characters sent back to the Enchanted Forest still have memories of Storybrooke. 

"As we laid out in the winter finale, Emma was the one who being back there was going to lose those memories and have this new life," Horowitz said. "The fairy tale characters get left with the pain and knowledge of what happened over the years that the show has been on and what they've been through. None of that is erased."

Snow White may also become pregnant, which would overlap with Ginnifer Goodwin's real-life pregnancy. But, Horowitz noted that Snow's storyline will follow what they've planned since the beginning.

Kitsis said Snow's pregnancy could cause a bit of chaos. "But you know, every time Snow White gets pregnant, hell gets unleashed," he said. 

There will also be a wedding, as well as a tough transition for Regina, who is feeling empty after losing Henry. While she does want another child, she will focus on healing first. 

"For Regina, it's what is going to make her heal again and where is she going to do," Kitsis said. "We know she filled the hole in her heart by doing the most selfless thing we've ever seen. She did what's best for Henry and gave him up to Emma, her sworn enemy, so they can have a better life. What happens when she returns to the Enchanted Forest? She needs to fall in love first." 

Meghan Ory, who played Ruby/Red Riding Hood/the Wolf in season one and two, may also be returning to the series. 

The next episode, "New York City Serenade," airs Sunday, March 9 at 8 p.m. on ABC.