A dark knight warrior in full spiked obsidian armor, holding a massive glowing purple greatsword plunged into the ground, fierce glowing purple eyes behind a horned helmet, long flowing black hair, surrounded by intense purple fire and dark energy, dynamic action pose, shattering rocks and debris, chaotic dark fantasy background, high detail, volumetric lighting, unreal engine 5 render, cinematic composition, 8k resolution, masterpiece