Question: Who plays the Wicked Witch of the West on ABC's "Once Upon a time" inspired by the novel by L. Frank Baum?
Context: Wicked Witch Software is a video games developer founded in 2001 by managing director Daniel Visser.  Originally operating out of Visser's residence working on Game Boy titles, Wicked Witch moved to a small office.  Wicked Witch has grown to be one of Australia's best known studios and is currently located in offices in Eastern Melbourne, Australia.  The company has worked with many local and international developers and publishers.  The senior staff are industry veterans, some who previously worked at Melbourne House and Torus Games.  Wicked Witch has released around 50 titles for PC, handheld and mobile platforms and worked on dozens of other projects across most major consoles including Xbox 360, PlayStation 2 and Wii.  Wicked Witch also owns a range of original products and game designs for many platforms, including one of the first MMORPG on the Java ME mobile platform. Gregory Maguire (born June 9, 1954) is an American novelist.  He is the author of "", "Confessions of an Ugly Stepsister", and several dozen other novels for adults and children.  Many of Maguire's adult novels are inspired by classic children's stories; "Wicked" transforms the Wicked Witch of the West from L. Frank Baum's "The Wonderful Wizard of Oz" and its 1939 film adaptation into the misunderstood green-skinned Elphaba Thropp.  The blockbuster Broadway musical "Wicked", at its height running nine companies simultaneously around the world, was inspired by Maguire's first adult novel.  The musical is the ninth-longest-running play currently staged in London's West End (as of September 2015), and the tenth-longest-running show in Broadway history. Wicked: The Life and Times of the Wicked Witch of the West is a novel published in 1995 written by Gregory Maguire and illustrated by Douglas Smith.  It is a revisionist look at the land and characters of Oz from L. Frank Baum's 1900 novel "The Wonderful Wizard of Oz", its sequels, and the 1939 film adaption "The Wizard of Oz".  Unlike the popular 1939 movie and Baum's writings, this novel is not directed at children, and contains adult language and content including violent imagery and sexual situations. Dorothy of Oz is a children's novel written by L. Frank Baum's great-grandson Roger S. Baum.  The book details Dorothy Gale returning to the Land of Oz when a Jester has been using the wand of the Wicked Witch of the West (which also contained the ghost of the Wicked Witch of the West) to take over the Land of Oz.  The book was adapted into a film called "" in 2014 by Clarius Entertainment. Wicked: The Untold Story of the Witches of Oz is a Broadway musical with music and lyrics by Stephen Schwartz and book by Winnie Holzman.  It is based on the 1995 Gregory Maguire novel "", an alternative telling of the 1939 film "The Wizard of Oz" and L. Frank Baum's classic 1900 story, "The Wonderful Wizard of Oz".  The musical is told from the perspective of the witches of the Land of Oz; its plot begins before and continues after Dorothy's arrival in Oz from Kansas, and it includes several references to the 1939 film and Baum's novel.  "Wicked" tells the story of two unlikely friends, Elphaba (the Wicked Witch of the West) and Galinda (whose name later changes to Glinda the Good Witch), who struggle through opposing personalities and viewpoints, rivalry over the same love-interest, reactions to the Wizard's corrupt government and, ultimately, Elphaba's public fall from grace. Out of Oz is the fourth and final novel in Gregory Maguire's "The Wicked Years" and was released on November 1, 2011.  "Out of Oz" brings a conclusion to the narratives spread across "The Wicked Years" while providing a revisionist look at L. Frank Baum's Land of Oz incorporating elements from Baum's series as well as the 1939 film adaptation of the original novel.  This novel presents an Oz in the middle of a civil war plagued with depression and adult situations, from the perspective of Rain, the young granddaughter of Elphaba Thropp, Maguire's reimagining of The Wicked Witch of the West. Son of a Witch (2005, ISBN  ) is a fantasy novel written by Gregory Maguire.  The book is Maguire’s fifth revisionist story and the second set in the land of Oz originally conceived by L. Frank Baum.  It is a sequel to "" (1995).  Like "Wicked", "Son of a Witch" differs from the original series in tone: while Baum's books were intended as children's literature, "Son of a Witch" elaborates a darker and more mature side of the lighthearted world of Oz.  In an interview that is included with the "Son of a Witch" audio CD, Gregory Maguire gave two reasons for writing the book: "the many letters from young fans asking what happened to Nor, last seen as a chained political prisoner, and seeing the Abu Ghraib torture photographs."  "Son of a Witch" continues the story after the fall from power of the Wizard of Oz and the death of Elphaba, Maguire's reinvention of the Wicked Witch of the West.  As its title implies, the story elaborates the life of Elphaba’s possible son, Liir. Zelena, also known as the Wicked Witch of the West, is a fictional character in ABC's television series "Once Upon a Time".  She is portrayed by Rebecca Mader and was first introduced in the second half of the third season, serving as the new main antagonist.  After making recurring appearances in both the third and fourth seasons, Mader was promoted to series regular for the fifth and sixth seasons and was the fifth season's secondary antagonist in the first half. The Wicked Witch of the West is a fictional character created by L. Frank Baum as the most significant antagonist in his classic children's novel "The Wonderful Wizard of Oz" (1900).  In Baum's subsequent "Oz" novels, it is the Nome King who is the principal villain; the Wicked Witch of the West is rarely even referred to again after her death in the first book. The Winkie Country is the Western region of the fictional Land of Oz in L. Frank Baum's classic series of Oz books, first introduced in "The Wonderful Wizard of Oz" (1900).  The Winkie Country is in the West, noted by later being ruled by the Wicked Witch of the West.  This quadrant is strictly distinguished by the color yellow.  This color is worn by most of the native inhabitants called the Winkies and predominates in the local surroundings.  The Winkies are relatively normal in appearance with the exception of their yellow-tinted skin.  Tin abounds there and it is said that the Winkies are some of the most skillful tinsmiths in the world.  This was the country once ruled by the malevolent Wicked Witch of the West before Dorothy Gale "melted" her with a bucket of water, as narrated in "The Wonderful Wizard of Oz".  After that, the Winkies asked the Tin Woodman to be their new monarch ruler which he gladly accepted.  He now lives in a vast palace made of tin that his loyal subjects built in his honor as a present for their new tin King.
Answer: Rebecca Mader