Create an artwork of a Skeleton Warrior for Dungeons & Dragons. The warrior is armored in ancient, battle-worn plate armor, adorned with remnants of once-shining metal. Its skeletal form is imposing and eerie, with glowing blue runes etched into its bones. The warrior wields a massive, enchanted greatsword that crackles with arcane energy. The background should depict a dark and mysterious dungeon chamber, with torchlight casting flickering shadows and illuminating ancient carvings on the walls, enhancing the undead warrior's menacing presenc