This is a challenging two part quest that may require the help of a group. This quest takes place in Tartarus.
To begin the quest you need talk to the pirate Laurens De Graaf. He can be found in the Bank located on the Tartarus pirate island of Erytheia.
Laurens De Graaf collects Ancient Daemon Skulls. He has spies who let him know where they may be found. He will help you find other rare treasures if you obtain a skull for him.
Be Warned: The skulls are very fragile and must be kept in your 'Main Backpack'.
If you succeed Laurens De Graaf will give you a 'Strange Key' for the Key Holder (a monster in the very bowels of a dangerous dungeon). If you manage this the Key Holder can open a gate to hidden treasures.