Zelena (Once Upon a Time)
In December 2013, Rebecca Mader was cast as the Wicked Witch of the West. She made multiple appearances during the second half of season three and was promoted to a series regular for the show's fifth season. The role of the Wicked Witch of the West was written specifically for Rebecca Mader. It was announced that the writers had chosen not to continue with Zelena's storyline and Mader would not be returning for the seventh season of the show. However, Mader later revealed that she would be returning for multiple season seven episodes.
A Curious Thing (Once Upon a Time)
It's eight months later. At the War Room, Charming, with Snow, Regina, Robin Hood, and Belle discuss how to defeat Zelena. Regina asks what gave them a head start in defeating her and Snow says that Rumplestiltskin warned them. They decide that they have to talk to Rumple so Robin and Regina lead the team as they enter his castle, and discover that he is now in a cage and talking in riddles. When Belle takes his hand, Rumplestiltskin tells them that "The light magic of Glinda, the Good Witch of The South" will defeat the Wicked Witch of the West, but adds sing-song clues to the message ("through the door step inside if pure of heart then she won't hide") after Snow questions him. Later that night in the forest, the rescuers find a door that leads to nowhere, fitting the musical description that Rumplestiltskin gave them. Snow and Charming step through, but Regina cannot because her heart is "heavy with vengeance". On the other side of the door, Snow and Charming meet Glinda, who has heard of Snow and wanted to meet her. Glinda tells the couple that she isn't powerful enough to destroy Zelena, because she was once a friend. Glinda then tells Snow about a pendant that she gave Zelena and that all of Zelena's magic rests inside of it, but only someone with the most powerful light magic will be able to remove it. Snow realizes that Emma Swan is the only one who can do this, and, since Emma's not with them, the only way to defeat Zelena is to enact the dark curse to get back to Emma.