The Heavenly Sword of Pain is a visually striking weapon with a sleek, elongated blade that curves slightly towards the tip, resembling a traditional katana but with a more pronounced, menacing curve. The blade is made of a dark, almost black metal with a subtle crimson glow emanating from intricate, vein-like engravings that run along its length, suggesting a cursed or bloodthirsty nature. The hilt is wrapped in aged, dark red leather, secured with ornate, golden metal fittings that feature small, sharp protrusions, adding to its dangerous aesthetic. The guard is circular with a complex, flame-like design, symbolizing the sword's fiery and destructive power. The overall design balances elegance with intimidation, perfectly suited for a high-level, legendary weapon in the Naruto universe.