Skull Key of the Heart
Key used to lift the entrance limit to the Hall of Suffering. Can only be used once a day outside the instance. After use, the effect disappears when the instance is reset. Cannot be exchanged or dropped. Can be stored in a private warehouse.
Not dropped by monsters.
Cannot be spoiled.
The chances are official (x1). On servers with x10, x100 and higher rates, drop and spoil come more often.