|Age||Not specified in the official anime. (Most likely in mid-late teenage range.)|
|Alternate Forms||Princess Kraehe|
|Relatives||adoptive father: The Raven
Actual parents’ names unknown.
|Anime Debut||The Duck and the Prince|
|Japanese Voice||Nana Mizuki|
|English Voice||Jessica Boone|
Rue, (“Rue Kuroha” in the manga spin-off,) (黒羽るう Kuroha Rū) is an advanced ballet student and is greatly admired by her peers. Like Ahiru, she also has a princess alter ego, the seductive and unkind Princess Kraehe.
When she was a baby, Rue was stolen from her parents by a group of crows who served her adoptive father, The Raven, who named her Kraehe. She grew up believing herself to truly be the Raven's daughter, who by some strange twist of fate, ended up being trapped in an "ugly human body".
One day, when being harassed by the crows who served her father, Kraehe was saved by Mytho, and she instantly fell in love with the heartless prince. When she asked her father about him, he told her that despite being their greatest foe, Mytho was the only person who would ever love her, and so she intended to make him her prince. For most of her childhood, the little girl always tried to get Mytho to pay attention to her, usually by dancing, but became miserable when he had to leave.
When Mytho went to study ballet at Gold Crown Academy, Kraehe was told by the Raven to 'pretend' to be a human girl and make Mytho fall in love with her. After slipping up and calling him Prince, she sealed away the memories of being Kraehe and took the name 'Rue'.
Rue is distant from her peers, so she does not seem to have any real friends. At times, despite being beautiful, she can be snobbish and possessive of Mytho but she has a good heart and a willingness to help those who are her friends. Her alter ego, however, is the darker side of Rue's personality: jealous, manipulative, and proud.
Rue has long wavy dark brown hair, red eyes, and pale skin. She is almost always in her school uniform and when she is not in her school uniform (such as in ballet class), her dancing outfit includes a dark red dress and tutu with matching pointe shoes and dark, sheer tights. As Princess Kraehe, her hair is similarly arranged like Princess Tutu's, with a feather raised above. She wears an entirely black dress with a black tutu consisting feathers, black tights, and black pointe shoes. Her black ballerina dress appears to be revealing to show her cleavage and the dress itself being backless while wearing the outfit.
When she transforms into Princess Kraehe, Rue is seen wearing the black tutu shoes after seeing the shoes are made by the ravens as the tutu shoes are fit and the black feathers encircle all over her body while she was nude (her uniform was burned during her transformation) until her black dress is formed.
As a child, she wears a black ballerina dress, white stockings and a matching black shoes.
When Mytho as Prince Siegfried turned her into his princess at the end of the anime, her school uniform morphs into a white gown with swan feathered designs at the hem of her dress. A gold crown appears on her hair.
Mytho/Prince Siegfried: Growing up barely knowing love, Mytho was the first person to show Rue compassion, so she fell in love with him despite her young age and his lack of emotion. After the Raven told her that only Mytho, a prince who loved all living beings, could love her, the sad and hurt girl attempts to make him do so.
At the beginning of the series, Rue is believed to Mytho's girlfriend.In reality, she uses his lack of emotions and tells him to pretend they are a couple because she's terrified of losing him to another person. Even after Mytho treats her cruelly as the Prince of Crows, Rue's love for her prince is absolute, to the point that when he's about to have his heart eaten by the Raven, she offers her own heart instead, which is what breaks off the spell and releases Mytho. In the end, the reborn Prince Mytho asks her to be his princess and Rue cries tears of joy, her greatest dream come true at last.
Ahiru/Princess Tutu: Rue is befriended by Ahiru when the clumsy girl brazenly approaches her without fear, and they become friendly. Ahiru's insistence that they are friends sometimes clash with Rue's true emotions. Rue deeply hates and fears Princess Tutu and plots to ruin her plans of collecting Mytho's heart because she considers Mytho as the only one who can love her despite how much she hates herself, so she won't allow the possibility of him falling in love with someone else. Her hostility worsens to the point of bringing Kraehe's sealed personality, and directly antagonizing her. At the end of the series, Rue and Ahiru reconcile themselves and are friends again.
Fakir: Fakir's overprotectiveness of Mytho cause Rue to see the knight as an obstacle for Mytho's attention.
Raven: Rue had always believed that the Raven was her beloved father, but he never treated her as such. He verbally and emotionally abused his adopted daughter purely to feed her fires of hate and jealousy and use her as the key to his freedom.
- In the English language, Rue has two meanings: a strong-scented evergreen shrub, or to regret something.
- In the Animax-Asia dub, Rue's alter-ego Princess Kraehe is renamed as Princess Claire.