Dimensional Key on Castle Battlements (Anime Style)

Anime-style fantasy scene on the crenellated stone battlements of a towering castle at dusk. A luminous dimensional key floats above the parapet, its metal surface etched with intricate runes that ripple with liquid light. The key casts prismatic highlights on the rough stone as a circular portal unfolds behind it, revealing a swirl of stars and nebulae. A lone apprentice in a hooded cloak stands at the edge, wind lifting their hair and cloak. Distant towers loom under a purple-blue sky with a pale moon and fluttering banners. Crisp cel-shaded rendering, bold linework, high-contrast lighting, and a dynamic camera angle from slightly below for epic scale. Vibrant colors, cinematic depth of field, and a sense of awe and mystery orbiting the dimensional key.