This cube craft is the Princess Shirahoshi, based on the manga series “One Piece”, this paper toy was designed by blackignus. Princess Shirahoshi, also known as the Mermaid Princess, is a giant smelt-whiting mermaid and the youngest of King Neptune's children. She was first mentioned by Pappug, claiming he knew her and even promised to introduce the Straw Hat Pirates to her when they arrived on Fishman Island. She is also the current form of Poseidon.
You can download this cube paper craft from here: The One Piece - Princess Shirahoshi Cube Craft Free Paper Toy Download