Enchanted Sword in an Underwater Cave

Photorealistic rendering of an ancient enchanted sword buried in the sandy floor of a dim, secluded underwater cave. Clear turquoise water with beams of sunlight piercing the ceiling, caustics dancing on stalactites and cave walls. The blade glows with a soft blue-green runic light, carved runes winding along the steel, emitting a magnetic shimmer. The hilt is ornate with pearl inlays and a dragon motif, a tangle of faded chain mail around the guard. Surrounding the relic are vibrant corals, sea fans, bioluminescent jellyfish, and curious small fish weaving through crevices while bubbles rise from the floor. Fine sediment swirls with every current, adding a sense of motion. Shot in ultra-detailed photorealism with dramatic underwater lighting, shallow depth of field on the blade, realistic refraction, and rich textures of metal, stone, and salt-water. Color palette of blues, teals, emerald greens, and warm gold highlights on the hilt. Mood: ethereal, mysterious, and epic.