The Hyakki Gokoku is a legendary, ornate katana with a hyper-stylized 3D anime aesthetic, featuring a sleek, curved blade that glows with a faint, ethereal blue light. The hilt is wrapped in dark, weathered leather, adorned with intricate golden engravings depicting mythical creatures, and the guard is a complex, asymmetrical design resembling swirling flames. The blade itself is polished to a mirror finish, with subtle, glowing runes etched along its length, suggesting its magical properties.