Dark fantasy anime illustration of Asta in Devil Union form

A hyper-detailed dark fantasy anime illustration of Asta from Black Clover in full Devil Union form, standing in a powerful low-angle pose against a pure black background with subtle swirling dark mist at his feet. He has wild spiky ash-gray hair, a single curved black demon horn on the left side of his head, one glowing crimson red eye and one sharp green eye, intense expression. Extremely muscular bare torso covered in jagged glowing red anti-magic veins and cracks, black tattered ragged cloak draped over one shoulder with a red emblem, large tattered black demonic bat wings with holes spreading behind him. He grips a massive black anti-magic sword with intricate red glowing runes and ornate hilt in his right hand, left hand open and clawed. Wearing dark torn baggy pants with straps and heavy black combat boots. Dramatic high-contrast lighting, sharp linework, monochrome grayscale with selective blood-red accents only on the veins, eye, sword and emblem. Epic, menacing, high-detail digital art in the style of official key visuals, 8k, intricate details.