You said magic was bad, and you're right, Bae. It's going to destroy my family.
Wendy Darling is a supporting character on Once Upon a Time. She met Baelfire after he entered her world via a portal. Since his arrival she visited Neverland in secret, bringing a dark force upon the Darling family.
Before the Curse
There's a reason it's called Neverland. Because once you set foot on its soil... the shadow never lets you leave.
Wendy is taken to Neverland. ("Second Star to the Right")
Baelfire falls through the portal and into a land without magic, arriving in 19th century London, England. He spends six months roaming the streets until one day he sees a rich family leave their window open and he climbs through the steal some bread. He is caught by a member of the family, Wendy Darling, who allows Bae to have as much as he wants, feeling sorry for him. She then keeps him up in her bedroom and sneaks him food for a while until eventually her parents find out. They are initially upset to have had this secret kept from them but they allow Baelfire to stay with them in their house, refusing to send him back on the streets or to a work house. Wendy is very happy about this and tells Bae of the shadow that comes to their window at night and shows her and her brothers magic, however, upon hearing of this, Bae tells Wendy not to interact with the shadow ever again, professing that magic is dangerous and destroyed his family. Later, the shadow arrives at the window and takes Wendy to Neverland, Bae tries to warn her against it but she seems too overjoyed with the idea, and flies away with the shadow. The next morning, Wendy returns, much to Bae's delight, but she seems less than happy, explaining that he was right and that magic is evil. She further explains that the shadow rejected her from Neverland as it wants a boy, but Bae assures her that it will not get one. They put the house on lockdown that night but the shadow gets inside with ease. He tries to go after Wendy's youngest brother but Baelfire refuses to let it, and so he goes with the shadow himself, after thanking Wendy for allowing him to be part of her family. Bae is flown over London city until he arrives in Neverland. ("Second Star to the Right") Wendy later returns to Neverland with the intention of rescuing Bae, as she can't bear the thought of him being without a family. Due to this act of bravery, Wendy is kidnapped and locked in a crate by Pan, being kept prisoner for centuries. ("Think Lovely Thoughts")
After the Curse
Well, it's a trade. When Pan lives... Henry will die.
Who could it be? ("Good Form")
When Neal, the grown-up formerly know as Baelfire, is knocked out, dragged to Pan's camp and hung up in a wooden crate, Pan orders for the Lost Boys to hang it up next to the "other one". This other, identical crate contains Wendy, who remains oblivious of Bae's presence in Neverland. ("Good Form") Wendy's cage continues to hang in Pan's camp whilst Neal's cage is relocated to the Echo Caves. Here, he is freed by Emma Swan and the others who have come to Neverland to save Neal's son Henry. They do this by each sharing their deepest darkest secrets in order to form a bridge to Neal, as well as open the crate he's locked up in. ("Ariel")
Wendy fools Henry, her best friend's son. ("Dark Hollow")
Wendy is let out of her cage by Pan and immediately asks if she's free yet, but, much to her dismay, Pan answers negatively, but adds that that doesn't mean she can't come out and play. He then uses her to trick his captive, Henry, whose heart will eventually be used to save his life. Pan does this by placing Wendy in a bed where she feigns sickness; Henry soon finds her, and she tells him that she's dying because the magic in Neverland is running out. She continues to win him over by telling him how much like his father he is, who she used to be friends with, and Henry is now more convinced than ever that he has to save magic (this being what he believes he's doing, as oppose to saving a dying Pan's life). Once Henry leaves, Pan emerges and tells Wendy that she played her part brilliantly, and it is learned that she only does Pan's bidding under threat of her brothers being killed. Meanwhile, in Storybrooke, John and Michael defy Pan's orders and order Belle and Ariel to get a message across to Henry's family, telling them to liberate a girl named Wendy, who is their sister. Upon hearing this request, Rumpelstiltskin promises try his best to do so. ("Dark Hollow")
Wendy explains what Henry's fate shall be. ("Think Lovely Thoughts")
Wendy continues to feign illness in order to fool Henry, and the young man is soon convinced to travel to Skull Rock to "save magic". When Henry's family, including Neal, break into Pan's compound and knock out the Lost Boys, Wendy calls out for help. She is soon found by Emma and Neal, the latter of which frees her and is touched to hear that she returned to Neverland to save him; they share a heartfelt hug. Wendy, after being wrapped up in a blanket, eventually tells the rest of the group that Pan has taken Henry to Skull Rock where he has told him he is going to save magic - but this is a lie. In truth, Pan plots to take Henry's heart and use it to save himself, as he is dying. When asked what will happen to Henry when his heart is sacrificed to Pan, Wendy explains that it's a trade, so when Pan lives, Henry will die. She remains at the camp with Tinker Bell and Captain Hook whilst the others carry out the rescue mission, and she is aware of the shock of magic that spreads across the island when Henry's heart is ultimately shoved into Pan's body by the young man himself. ("Think Lovely Thoughts")
Wendy believes in Tink. ("Save Henry")
The unconscious Henry is taken by his parents back to the Lost Boys' camp, where Wendy witnesses Emma bribe the boys themselves with the prospect of home; they are eventually coerced into giving away Pan's location, and it isn't long before Henry's heart is retrieved and returned to his body aboard the Jolly Roger. Thanks to the shadow, the ship begins to fly, making its way to Storybrooke, and as they head home, Wendy approaches Tinker Bell. She reveals to the fairy that she kept a vial of dead pixie dust all these years, and thought maybe Tink could make it work. Tink then reveals to the young girl that she can't perform magic anymore, not since she lost her wings, but Wendy assures her friend that she believes in her. Wendy sits back and continues to fly back to her loyal brothers alongside her new comrades. ("Save Henry")
A Darling reunion. ("The New Neverland")
Wendy, along with everyone else aboard the Jolly Roger, arrives in Storybrooke, a small town in Maine, where she is spotted quickly by her brothers John and Michael Darling. Spotting them back, she runs up to them and hugs them, surprised and overjoyed to be seeing them again, now as adults. She then asks them if they remember Baelfire, and reintroduce them to the adult version known as Neal Cassidy. Baelfire and the three Darlings then share a joyous group hug, happy to be reunited at long last. But they are soon put under threat when Pan, who's disguised as Henry Mills, steals a Dark Curse capable of wiping the minds of all those in Storybrooke, freezing them in time. ("The New Neverland")
Gallery of photographic stills released to promote the character.