Create a highly realistic image of an Oni, a fearsome demon or ogre from Japanese mythology. The Oni has red skin, large horns on its head, sharp teeth, and white hair. It is wielding a katana, showcasing its immense strength and power. The Oni has large, muscular features and is captured in a dynamic pose, roaring fiercely. The image should focus on the upper half of the Oni's body with a professional, detailed angle. The scene should emphasize the terrifying and powerful nature of the Oni, with intricate details on its skin, horns, hair, and weapon, making it look very realistic.