One Piece Online 2: Pirate King OP2 URL: op2.joygames.me Treasure Hunter is an Instance in the pirates’ world which player can challenge once per day Players can choose ten of the crew members who are higher than 20 levels, including the Main, to join before challenging the Instance. Before each battle, player can select five among the crew members to participate in the fight, and selected crew members will be locked after the fight begins. The locked crew members cannot be changed.