Design a majestic, curved longsword inspired by ancient runes and Elden Ring's mystical lore. The blade should feature intricate carvings of a dragon, symbolizing power, and the hilt wrapped in dark leather with a gemstone embedded in its pommel. The sword should be sleek yet formidable, exuding a mix of elegance and dread. Its core ability should channel black flame and lightning, giving it a dual-elemental attack reminiscent of forbidden magic