Pixies
They're fickle, evil-tempered, loose moraled and irresistably cute (so the mortals say). Pixies are knee-high berserker warriors, who might be cute under the filth and war paint. Only two things placate them: Faewine and mushrooms. Don't have them? A likely story! They tear ships to shreds trying to locate them, meaning a carefully collected treasure hoard can be ruined by hungry, sober, pixies in a matter of minutes. Beating up on them won't stop them and you just can't kill them. They reassemble and leave, to hunt you down in greater numbers later. But pixies also have attention spans no longer than a pin, so if another ship comes along, they'll leave you alone and forget you.