An intricately designed Frostmourne sword, coursing with icy blue lightning, emanating a cold, eerie magic glow, engulfed in swirling blue and white frost flames. Sparks of lightning crackle around the blade, with glowing embers drifting in the air. Arcane runes are etched along the blade, pulsing with dark energy. The hilt is adorned with an ivory handle, and the handguard is set with jagged, glowing crystals that radiate a chilling aura. Rendered in 4K, masterpiece quality, with absurd resolution and concept art detail, all set against a stark black background, highlighting the sword's ominous, otherworldly power