Envision a monumental fortress crafted entirely from shimmering obsidian, standing tall against a backdrop of a vibrant twilight sky. The fortress is adorned with intricate carvings that reflect the fading sunlight, casting mysterious shadows. Surrounding the structure, a swirling mist clings to the ground, while distant mountains loom, their peaks kissed by the last rays of sun. The scene conveys an aura of ancient power and untold secrets.