Alien Sentinel in a Photorealistic Fortress

Photorealistic depiction of an alien sentinel inside a colossal fortress hall. The alien is tall and slender, with slate-gray skin, subtle bioluminescent blue patterns along its limbs, large almond-shaped eyes, and delicate ridges along the skull. It wears seamless, organic armor that appears grown from its body, a dark alloy with iridescent facets. The fortress is immense: rough stone walls, sweeping arches, carved runes, and torches flickering in wall sconces. Damp moss clings to the pillars; rain-slick flagstones reflect the torchlight. In the background, towering gates, gargoyle sculptures, and crystalline clusters embedded in the walls. The atmosphere is cinematic and moody, with high dynamic range lighting, long shadows, and a shallow depth of field (85mm lens, f/2.8) to keep the alien sharply detailed while the distant fortress blurs softly. A sense of awe and ancient power pervades the scene.