<Li> "The Final Battle" </Li> <P> Emma Swan is a fictional character in ABC's television series Once Upon a Time . She is portrayed by Jennifer Morrison, by Abby Ross as a teenager, and Mckenna Grace as a child . Emma first appeared in the series's pilot as a bail bond agent in Boston, Massachusetts until she meets her biological son Henry, whom she gave up for adoption 10 years before, and learns she is the daughter of Snow White and Prince Charming . Henry urges Emma to go to the fictional town of Storybrooke, Maine, to break a curse enacted by the Evil Queen and to restore the fairy tale characters' happy endings . </P> <P> The daughter of Snow White and Prince Charming, an ex-bail bonds collector, town sheriff of Storybrooke and Henry Mills' biological mother . Morrison described her character at the beginning of the first season as "broken, damaged and worldly". During the fourth season finale, "Operation Mongoose", Emma absorbs the power of the Dark One into herself to save Storybrooke . In order to successfully create a dark version of Emma, Morrison explained that "In order to build Dark Emma, I've been doing a bunch of research there with some of their mythology books and old fairy tale books and just looking back through the history of swans and the etymology of' Swan"' and explained that Emma's rate of evolution "challenged (her) on a daily basis". Emma became the primary antagonist of the fifth season's first half, until the end of the season's eighth episode when her real plans are revealed . </P> <P> Morrison's portrayal of Emma has received praise, with some reviewers noting a feminist twist in the depiction of fairy tales and a strong female lead . She is loosely based on the title character of the fairy tale "The Ugly Duckling", a swan which was lost and raised by ducks, before finding its birth family and recognizing its true nature, while her Dark One side is loosely based on Odile the Black Swan from the ballet "Swan Lake". It is revealed in the Season 6 episode "Tougher Than the Rest" that she chose the last name Swan when she was young after a friend mentioned that story . </P>

When does emma turn into the dark one