terrifying ancient demon lord wandering a scorched ash wasteland, obsidian skin texture with glowing magma cracks, massive twisted horns crowning a skull-like face, wearing tattered ceremonial robes that dissolve into smoke, background of jagged obsidian mountains and a red lightning storm, swirling ash particles, low angle shot looking up, ominous and oppressive atmosphere, dark fantasy oil painting style, intricate details, dramatic shadows, rim lighting