This cube craft paper toy is Akakabuto (aka Onikubi or Demon Bear), from an adventure manga named Ginga: Nagareboshi Gin, the papercraft created by scarykurt. Akakabuto's name means "red helmet" for the blaze red mane of hair on his head.
Akakabuto has terrorized the humans and dogs of the Ohu Mountains for years. His right eye was shot out by Gohei six years ago. Because of the damage, Akakabuto is unable go into hibernation and grows to an unimaginable size but also made him unpredictably mad and bloodthirsty. Gin finally slays him in the final battle, cutting his head off with the Zetsu Tenrou Battouga attack. In the English Ginga Densetsu Weed manga, he is actually called "Red Helmet".
You can dowload this cube papercraft toy here: Ginga: Nagareboshi Gin - Akakabuto Cube Craft Free Paper Toy Download