This cube craft paper toy is Princess Tutu, Duck's alter ego, from same named anime / manga series, the papercraft was created by SKGaleana. Unlike Duck, Princess Tutu is a very graceful and elegant ballerina. Her mission is to find and return the missing pieces of Mytho's heart.
In The Prince and the Raven, Tutu was a minor character that confessed her love to the Prince - which, because of a curse, caused her to turn into a speck of light and vanish. Still in love with Mytho, her quest is to gather the pieces of his missing heart and return them to him. Hidden in the hearts of the residents of Gold Crown Town, Tutu can retrieve Mytho's heart shards by dancing with them and helping them to realize their true feelings. However, Tutu's curse still haunts her, so as much as she encourages others to be true to their hearts, she's unable to speak her own true feelings aloud.
In Duck's eyes, Princess Tutu is everything she is not. She's poised, graceful, an elegant and skilled dancer, and all-around nearly perfect. Duck often struggles with comparing herself to her alter-ego, unsure if Tutu is really her, or simply the character from the story somehow working through her. Also, while restoring Mytho's heart means he can feel joy and love, it also means he can feel sadness and pain, which causes Duck to doubt if her actions are truly helping him. Because of this, she actually has quite a bit of angst throughout the show - but she pushes forward, hoping that in the end she'll be able to see Mytho smile.
Duck takes on a drastic change in both appearences and wardrobe style upon transforming into Princess Tutu. Her long braid, freckles, and layered hair strands disappear, and her height increases slightly. However, she still retains her red-orange hair and blue eyes, including the large strand of hair ressembling much like her head feather as a duck. Her outfit seems to be inspired from Odette's costume in Swan Lake as the dress is white and white feathers circle Princess Tutu's hair. She also wears a small gold crown on the top of her head, pink pointe shoes, and a pink tutu underneath her white dress. The outfit seems to be renewed with each transformation, seen when, despite having her outfit ripped by the Ghost Knight in Episode 18, upon transforming again later it is like new with no rips or marks. [Source: wiki]