The Dragon key is a key made out of Orikalkum that is reforged during the Dragon Slayer II quest. After a player has collected all four dragon key pieces, they must be brought to the Ancient Cavern to be forged into the complete key. It is then used on the grandiose doors underneath Lithkren to open the Lithkren Vault.
This item was dropped by a slain dragonkin during the assault on Lithkren in the Fourth Age by Robert the Strong, Aivas, Camorra and Tristan. Fearing what the key may have opened, the heroes decided to split it into four pieces and hid them throughout the world.