Ailsa is the daughter of a Selkie and born of the sea. She was born after her mother found her seal skin and left her husband on land to return to the sea. Ailsa has never known her father because her mother has never spoken on him, holding a grudge against the man for forcing her to stay with him for so long. As Destiny would have it, Ailsa will one day have her own seal skin stolen by a young man and live with him as his wife until she can reclaim her seal skin.
Ailsa is shy and nervous in crowds and she often sits in the back of the class, just to make sure she can see where everyone is. She has a personal bubble that she doesn't let very many people into because she's simple scared to trust people. Her hesitation to trust people stems from her fear of them finding out that she's a Selkie and trying to find where she's hidden her seal skin. She's not hard to get along with, really, just hard to talk to because of her anxiety. It's the rare person that can befriend her and gain her trust.
Even when someone does manage to gain her trust, Ailsa is slow to open up to them. She'll talk more and begin to smile, even joke, but it takes time for her to become comfortable with someone. Eventually, she proves herself to be a loyal friend, sweet and caring, and very protective. If someone threatens her friends in any way, Ailsa gets defensive, sometimes even bodily so, unafraid to tackle whoever is causing her friends trouble.
Ailsa torn between staying at school and returning to the sea. As much as she likes it at Ever After High, she misses swimming with her family and dancing on the beach under the moon with her Selkie sisters. She loves being at school, loves learning, but she's constantly nervous about her seal skin being stolen while she's in class. She desperately wants to break away from her destiny, but because of her nerves, she's afraid to declare herself a Rebel and try to change her fate, so she takes a firm stand as a neutral party in the Royals vs Rebels debacle.
Ailsa's favorite hobby is swimming, though she believes she swims better in her seal form. She very rarely takes out her seal skin to swim, however; she does not want people finding out her secret.
When she's not swimming, she'll wander around Book End, visiting shops and cafes.
- The Selkie - Ailsa's mother, the Selkie once had her seal skin stolen by a man who made her his wife. After several years, the Selkie was able to retrieve her stolen seal skin and left her husband and two of her children behind as she returned to the sea. Shortly after returning to the sea, she gave birth to Ailsa, the only one of her husband's children to gain a true Selkie heritage.
- Father - Ailsa does not know her father, or even his name. Her mother mostly refuses to speak of him, referring to him only as Ailsa's father, never as her husband.
- Brother and Sister - Ailsa knows that she has a brother and sister somewhere on land, much older than she is. She does not know their names, much as she does not know her father's.
- None yet
- Ailsa does not have a romantic interest and she is not particularly fond of gaining one, as her Destiny says that her future husband steals her seal skin and forces her to remain human for several years.
- Ailsa is named for the Ailsa Craig, an island off the coast of Scotland.
- The particular version of the story of the Selkie Ailsa was based on was written by Mara Freeman in 1995, based on the story of the MacCordum clan, who claim Selkie ancestry.