On the latest episode of "Once Upon a Time," a major character met his demise at the hands of the "Dark One."

In "Quiet Minds," Zelena/Wicked (Rebecca Mader) asks a flying monkey to find the missing Gold (Robert Carlyle), who is seen running through the forest.

Later, Emma (Jennifer Morrison) sees Neal (Michael Raymond-James) at the hospital, and sees that he has the burn of a triangular symbol on his palm.

In the fairytale land of a year ago, Belle (Emilie de Ravin) and Neal are talking when they encounter Lumiere, who says he was trapped as a punishment from the Dark One. He shows them a key to a vault that has the same triangular sign on it, and Neal agrees to help him. After they leave, the Wicked Witch enters, revealing it's a plot she orchestrated.

Lumiere later confesses that he works for the Wicked Witch, who cast a spell on him.

Neal then puts the key into a spot on the ground and pushes. It expands and burns, and a door to a portal appears in the ground. Rumple (Robert Carlyle) then emerges from the portal. 

Meanwhile, Regina (Lana Parrilla) is searching for the Wicked Witch. She catches an arrow, and discovers it's from Robin Hood (Sean Maguire), who mistook her for Wicked. He apologizes, and the two team up to track down the Wicked Witch.

They search for magical traces in Wicked's cabin. The two begin flirting, and she sees a tattoo of a lion on his arm, which indicates that he's her soul mate.

In Storybrooke, Emma and David (Josh Dallas) find Gold in the woods, but a flying monkey flies down at that very moment. Gold runs away as Emma and David fight off the winged creature.

Later, Belle talks to Emma about how the Dark One has returned, and that Neal's death is imminent. Just as Belle finishes that statement, Neal yells and falls to the ground.

Back in Fairytale land, Rumple sees Neal on the ground, and the Wicked Witch appears. Wicked Witch orders Rumple to kill Belle, but Lumiere stops her by encircling her in flames.

In Storybrooke, Gold tells Neal that the Wicked Witch is Zelena. Neal ends up dying from the Wicked Witch, and Emma is devastated. Emma tells Henry that she's going to stop at nothing to find the Wicked Witch.

Co-executive producers Adam Horowitz and Edward Kitsis spoke to TVLine about what Neal's death means for the future of the series.

They said Neal's death was difficult, but felt it was a necessary decision. 

"The biggest con for us was we love Michael Raymond-James and we love that character," Kitsis said. "For us, it was a creative decision and it was an evolution in the character."

"It was a storytelling choice but one that was made in the context of the larger story we're trying to tell," Horowitz said.

"We leave it to you and the audience to judge how you feel about it, but for us as storytellers, that was where it felt like it had to go," he continued. "We didn't want it to be exploitative, we didn't want it to be about shock, that's why it wasnt in the promos.... It was something we wanted to be emotional and real."

Horowitz also said that Neal's death will "raise the stakes for the characters with regards to the Wicked Witch and what's going on in Storybrooke, but even more importantly, on the larger canvas of how these characters are growing and interacting, for the story beyond this, this is a pivotal moment for many of them."

As for Rumple and Belle's relationship, Emilie de Ravin told TVLine that the pair has a very "Romeo and Juliet" relationship.

"It's not your vanilla 'I'm going to make coffee and pancakes for you' thing, which for me is perfect," she shared. "Instead of always being beautiful and perfect, I always prefer having something that threatens the demise of their relationship. Belle's become stronger because she's had to deal with him, even though she was a strong character from the beginning - but she's also given him strength. He's had power, and she's had the strength."

Jennifer Morrison also hints that her character, Emma, may learn some magic on a future episode: "Regina's a bit annoyed because Emma wasn't really into learning magic in Neverland, so there's some banter back and forth about my 'reluctance' to be magical."

But with the Wicked Witch on the loose, Morrison said that "Emma has that extra motivation to reach into place in herself that she's not necessarily comfortable with."

In other "Once Upon a Time" news, a "Wonderland" character will join the "Once Upon a Time" world.

Michael Socha of the recently canceled spinoff "Once Upon a Time in Wonderland" will join the fairytale drama when it is officially renewed for a fourth season, The Hollywood Reporter confirms.

On the next episode of "Once Upon a Time," called "It's Not Easy Being Green," Zelena and Regina will have a series showdown. 

The episode's synopsis reads: "With Rumplestiltskin as her slave, Zelena challenges Regina to a fight to the death and shocks the Evil Queen with the reveal of their familial connection, and the town lays Neal to rest. Meanwhile, back in the past in the land of Oz, a jealous Zelena asks the Wizard to send her to Fairy Tale Land after discovering that she has a sister, Regina, and that Rumplestiltskin is training her to become a powerful force to be reckoned with."

Check out photos from the next episode here, which include stills of the Wicked Witch fighting with Regina on the streets of Storybrooke.

Watch the promo below for next week's episode, which airs Sunday, April 6 at 8 p.m. EDT on ABC.