Elegant Oni Warrior Portrait

A refined anime illustration of a tall adult oni woman in a calm, elegant full-body portrait, standing in three-quarter view with her hands folded over the pommel of a large upright sword. She has very long straight [hair color] hair flowing past her knees, pale skin, pointed elf-like ears, narrow crimson eyes, and two smooth curved red horns rising from her forehead. Her expression is cool, aloof, and slightly melancholic. She wears a [outfit style]: a fitted white dress-like inner layer with a deep neckline, a black obi and layered waist ornaments, a translucent patterned outer robe with subtle geometric motifs, wide sleeves lined in red, and a short skirt hem decorated with smoky dark flame shapes. Her forearms are covered in polished silver armor gauntlets, adding a warrior feel. The sword is oversized and heavy, planted vertically before her, with a black blade and hilt, metallic guard, and vivid glowing red flame-like patterns running down the center. The composition is graceful and balanced, mixing Japanese traditional aesthetics with dark fantasy. The background is a soft pale lavender-gray decorative collage with a circular window framing Mount Fuji and a winding river landscape, delicate floral silhouettes and blooming branches, abstract cloud motifs, hanging tassel ornaments, geometric textile patterns, and a red sun-like circle on the right. Use muted whites, lilacs, gray-violets, black, and deep crimson as the main palette. Add subtle paper texture, clean linework, soft cel shading, delicate highlights, and an ornate high-detail anime style. Make the overall mood serene, noble, mystical, and slightly ominous, like [character name] in a luxurious Japanese fantasy key visual.