Wendy (ウエンディ, Uendei) is a first-string member of the Noah's Ark Circus. As a flying trapeze artist, she conducts her performances alongside Peter; together, they are deemed as a duo "in perfect sync."
Wendy appears as a small child with large, red eyes. She has her brown hair up in two buns and wears a small, black crown on her head. She dresses in a cinnamon pink dress with black stripes, black tights, and shoes with a ball on each toe; her casual attire for going out consists of a cape-like coat and gloves, with the images of stars and moons on them. Additionally, she dons a ribbon as a choker around her neck and ribbons around her forearms. As part of her circus act, Wendy puts on makeup that consists of false eyelashes and three diamonds painted under her left eye.
In the past, Wendy wore a ponytail on the left side of her head, an over-sized dress and one shoe. Despite this seeming to be several years ago, she does not appear any older now than she did then; her growth is abnormally stunted.
Wendy is soft-spoken and reserved and usually defers to Peter to do most of the talking. However, when she does speak, she presents herself in a mature manner, such as when she comforts Beast. Like the other first-string circus members, she is very concerned with completing the tasks set out to them by Baron Kelvin, and seems to have no qualms about kidnapping or murdering individuals while accomplishing these tasks. She cares deeply about the other first-string circus members, perhaps more than she cares about Baron Kelvin; she is most attached to Peter, as she is almost always in his presence.
Wendy grew up in an alley in the East End, referred to as a gutter, with the other first-string circus members, less Snake. Joker stated that they came together because they were each defective in a way. In Wendy's and Peter's case, they are trapped in children's bodies. For this reason, even though they seem to be the youngest of the circus members, they may actually be significantly older; this has been hinted at, such as when Peter called Doll, who appears older than both Peter and Wendy, a child.
Ten years ago, Doll rushed up to Joker one day with a tooth in her hand. She gleefully exclaimed that it fell out, believing that she would later get a coin from the Tooth Fairy and promised them that she would buy them all bread afterwards. Unbeknownst to her, Wendy, Joker, Beast, Dagger, Peter, and Jumbo proceeded to work on manual chores earnestly all night long in order to earn a single coin for Doll. They were relieved to see they made it on time as they placed it beside her whilst she was sleeping. The next morning, an oblivious Doll showed off her coin to them, stating how happy she was that they could eat bread with it and an exhausted but happy Wendy laughed along with her. However, in the belief that the Tooth Fairy would give her more coins, Doll later attempted to take out more teeth that weren't wobbly, to the dismay of the others.
As thieves, they were unsuccessful, and they barely managed to survive. At some point, Baron Kelvin found them in the alley and adopted them. After living at his manor for some time, they decided to start a circus, and Wendy and Peter formed the trapeze act.
At a circus show that Ciel Phantomhive and Sebastian Michaelis attend, Wendy and Peter are presented by Joker as the duo that forms the flying trapeze act, and they perform fittingly. After the show, she and Peter mock Sebastian for getting bitten by a tiger. Later, Joker introduces Ciel and Sebastian, new second-tier members, to Wendy and the rest of the group.
Later, right before a performance, Wendy twists her ankle, which prevents her from going on. Joker, who is carrying her on his back, asks Sebastian to stand in for her. The next night, Wendy has gathered with the other first-string members, except for Snake and Joker, the latter of whom had left the night before to go see Baron Kelvin. They have learned that Ciel and Sebastian, who had infiltrated their tents, have left, and decide that remaining where they are would be dangerous. Dagger suggests carrying out the mission once Joker returns, but Wendy points out that they cannot wait that long. Beast offers to go inform Joker, but Wendy insists that her battle power will be needed. As a result, Doll is sent to inform Joker instead. They agree to carry out the mission the next evening, to give them enough time to complete the task.
The following day, they are packing up their belongings. Wendy points out to Beast that she has been acting strange since yesterday. When Beast appears sad and upset that they will not be waiting for Joker's return, Wendy comforts her by asserting that she can talk to Joker soon.
That night, they go to Phantomhive Manor, where they split up in an attempt to accomplish their goal quickly. After a little while, Wendy and Peter hear Jumbo calling out to them, telling them to leave the mansion. When they run to his location, they discover that Finnian has already killed him. Angrily, they approach Finnian and engage in a brief battle. They decide to pull a wire between the two of them and split him in half. As they begin their descent, Wendy is killed by an unseen sniper, who is later revealed to be Mey-Rin.