|Anime Debut||The Duck and the Prince|
|Japanese Voice||Naoki Yanagi|
|English Voice||Jay Hickman|
Once a noble and kind fairytale prince, he lived to protect the weak and the needy. His heart was shattered to seal the monster Raven away. Now a talented and popular student at Gold Crown Academy, he possesses no emotions, nor memories of his past life, and is largely dependent on Fakir for his well-being. When Drosselmeyer decides to use Duck to become Princess Tutu, she gathers the lost heart shards of Mytho's heart and returns them. Meanwhile, Rue's alter ego emerges from her and becomes Princess Kraehe , trying to possess him for herself. When she soaks Mytho's heart shard of love in the Raven's blood and when the shard is returned by Princess Tutu, Mytho struggles to free himself from the blood and then transforms to a crow later. Rue then reveals her feelings to him saying the words, "I love you!" and he becomes restored to a human. The last shard of his heart, which was Princess Tutu's pendant, is returned to him and he becomes Prince Siegfried again, defeating the Raven and asks Rue's hand in marriage before he returns to the story.
Mytho is utterly emotionless at the beginning of the series so he seems unable to think for himself and listens to almost anything told to him. With the help of Princess Tutu returning his heart, he begins to develop emotions and slowly returns to the way he was long ago. It begins with negative heart shards only to get positive towards the finish. As Prince Siegfried, he is very brave and noble but as the Prince of Crows, he is deceitful and coarse towards others, even Fakir and Rue.
Mytho is reserved, composed, and patient with others, though he also has virtually no agency of his own and acts on even his slightest whims, such as leaping out of a window to save a bird that he perceives to be in danger, despite the fact that it can fly and is at no risk of falling, and is otherwise quick to sacrifice or cause injury to himself to this end. He is also very curious about his emotions, though once he begins to experience them again is overwhelmed and confused by them.
Mytho is a young man with silvery-white hair and large amber eyes. He mostly wears the Gold Crown Academy's uniform but in other times in both the pilot episode and Episode 15, he wears only a loose white long sleeve button shirt from his school uniform when staying inside their dorms along with Fakir. At ballet class Mytho wears a white short-sleeved shirt, black pants, white stockings, and white ballet slippers. While having the Raven's blood flowing inside him, his outfit as the Prince of Crows is a black outfit and with wings on his arms that becomes gray. When he becomes a raven then returning to his human form after hearing Rue's voice and fighting against the Raven, Mytho wears his white long sleeve openly button shirt with two shreds in both of his sleeves, a matching pants and shoes from his school uniform and wields a sword.
Later on when his heart became fully restored in Episode 25 and as Prince Siegfied, he wears a gold crown on his head and a long-sleeved royal blue tunic with gold lining designs, a collar designed with long white feathers, and an iris blue chemise worn underneath. Mytho also wears a white hose, a white cape, and white ballet slippers.
Mytho's heart shards also resembles his current appearance when Princess Tutu retrieves the shards to restore Mytho's heart.
Ahiru/Princess Tutu: Ahiru is one of his many admirers. Mytho does not notice her at first, but eventually grows to think of her as a friend as he regains his heart. Princess Tutu, on the other hand, becomes someone Mytho both longs for and fears for reasons he doesn't understand.
Rue/Princess Kraehe: Rue has been in love with Mytho since she was a little girl, but though he treated her kindly, he could not return her love without his emotions. The two appear as a couple at first, but only out of Rue telling Mytho to be hers. When he is corrupted by the Raven's blood, he treats Rue and Kraehe with scorn and mocks her constantly. However, when Mytho regains his past identity and Rue shows her willingness to sacrifice herself for his sake, he realizes that Rue is his true love, and makes her his princess.
Fakir: Fakir is Mytho's roommate, guardian, and protector. The majority of what Mytho does is under Fakir's orders. If he is not obedient, Fakir will punish Mytho and certain times the punishment can get physical. It is unknown why Fakir tends to scold Mytho in the beginning of the anime. It seems that Fakir was cold and ruthless towards Mytho. However, deep down, Mytho is one of the few people that Fakir shows his gentle side to. Fakir does care deeply for the prince and is willing to do everything in his powers to protect Mytho. In the near end of the anime, both Fakir and Ahiru are also helping Mytho as Prince Siegfried to rescue Rue from the Raven. Mytho also made peace with Fakir before he departed with Rue.
- His true name, Siegfried, is the name of the prince who fell in love with the swan princess, Odette, in Swan Lake.
- His common name, Mytho, may refer the term Mythos which is the set of rules that govern the universe in which a story is placed.
- Mytho may be based upon Anthy Himemiya, one of the two protagonists of Revolutionary Girl Utena, the collarabtive work which Princess Tutu is considered a spiritual successor to. Mytho and Anthy both have the common features of names derived from Greeks, a seeming lack of emotions, extreme reliance upon others (Mytho is unable to discern when he is hungry or tired due to his aforementioned lack of emotions, Anthy is emotionally dependent on those around her - particularly her abusive brother - and finds looking after herself difficult), are brought out of their shell gradully by their love interests, and both have undergone a tremendous amount of self sacrifice and tragedy in their backstories. Mytho may also borrow from Prince Dios, another important character from Utena, as both are princes and heroic characters who have fallen from grace and despair.
- In the both the English dub and the Animax-Asia dub of the series, his name is sounded like Mewtwo referring to the character of both the anime and video games, Pokemon.