This cube craft paper toy is Mytho, Prince Siegfried from the story, The Prince and The Raven, written by Drosselmeyer,who shattered his heart in order to defeat the Raven, from the anime / manga series Princess Tutu, the papercraft was created by SKGaleana.
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 a young man with silver-white hair and large amber eyes. He mostly wearing Gold Crown Academy's uniform but in other times, he wears a white long-sleeved blouse that consists buttons and a collar. 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 grey. Later on when his heart became fully restored in episode 25, 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 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. [Source: wiki]
You can download this cube paper craft toy here: Princess Tutu - Mytho Cube Craft Free Paper Toy Download