Eldritch Obsidian Citadel Horror Poster

A dark, monolithic 3D poster concept depicting a gargantuan dark fantasy obsidian citadel towering over an ethereal sea of swirling black mist under a dark eclipse sky. The citadel features impossible jagged gothic architecture, sharp spire towers, and subtle crimson light pulsing from narrow window slits. In the sky above, a massive dark solar eclipse with a glowing blood-red corona casts eerie, ominous light across the jagged mountain peaks framing the fortress. The atmosphere is thick with volumetric fog, floating dark cinders, and glowing crimson embers drifting through the air. The lighting is atmospheric and low-key, dominated by deep shadows, cold moonlight highlights along the sharp edges of black stone, and intense crimson glows from the eclipse and fortress windows. Framed in a powerful vertical poster layout, looking dramatically upward from a low valley floor to accentuate the imposing size and horror of the citadel. Captured with a virtual 21mm ultra-wide lens, producing intense dramatic perspective lines that pull the viewer into the dark realm. Rendered using Octane Render, featuring complex volumetric fog simulation, detailed rock displacement maps, high-contrast dark fantasy color grading, and chilling cosmic horror mood.