My though is he'll start small and work up. First just whispers, but every display of sexual energy and frustration will make him a little stronger. Soon he'll be humiliating and mentally torturing the lady pirates without even leaving the chest. When he has one of the ladies so under his thrall that they open the chest, the real madness kicks off.
Bondage, humiliation, sex, psychological torture - too the point that when the ship is found the ladies are worshipping him like a god, and have to be put down.