|“||Yes, I am a crow. And I alone am the true Prima donna!||„|
|~ Princess Kraehe|
She was voiced by Nana Mizuki in the Japanese version, and Jessica Boone in the English version.
Kraehe was stolen from her parents as a baby by crows that served the Raven. From her early years, the Raven raised her on his blood, effectively making her part crow and instilling her with his power. She had always believed that she was truly the Raven's child, but was born in a human's body by some bizarre fluke of fate.
While still very young, Kraehe met and fell in love with Mytho, the remains of Prince Siegfried, who was the Raven's archenemy. Sensing a chance to turn the prince over to their side, the Raven ordered Kraehe to make Mytho fall in love with her.
For years, Kraehe attempted to make Mytho pay attention to her, usually by dancing, but her fear of losing Mytho's affections made her confidence very fragile. Realizing that Mytho's lack of a heart meant that he could not truly feel love for her, Kraehe asked Mytho to tell her that he loved her, which he accommodated to. After Mytho went to attend ballet class, Kraehe joined as well, but decided to hide her identity, by taking the name Rue and sealing away her memories of being Kraehe.
When Princess Tutu began collecting the shards of Mytho's heart, Rue's fear that she could lose Mytho was enough to surface Kraehe's personality. The princess of the crows once more, Kraehe set out to stop Tutu from taking Mytho away from her. When all of her attempts failed, she turned to the Raven for help. Her father told her to soak the shard containing the emotion of love in a bowl of his blood then give it to Mytho. With the Raven's blood inside him, Mytho was corrupted into becoming the evil prince of crows. At first, Kraehe was happy that Mytho sided with her, but soon came to regret her decision as Mytho's cruelty grew fiercer.
Eventually, a magic puppet named Uzura accidently made time turn backwards, and Kraehe saw her childhood, and finally saw the truth about herself: she was not a crow, but an ordinary human stolen from her family. Knowing this, the Kraehe personality disappeared, and Rue was a powerless girl permanently.
- Kraehe's Japanese voice actor Nana Mizuki also voices Fate Testarossa, Wrath, Alois Trancy, Irias Reginleif, Maria, and Inner Moka Akashiya.
- Kraehe's English voice actor Jessica Boone also voices Doctor Arakawa.
- Kraehe was inspired by the character Odile from Swan Lake.
- Kraehe is the romanization of Krähe, the German word for crow. Her human name, Rue, is likely originating from the English word meaning remorse.
- In the Animax-Asia dub, Rue's alter-ego Princess Kraehe is renamed as Princess Claire.