These guys apparently had the same idea as us, to become pirates. Desiring to strengthen their bodies, they gave in to practice of consuming 'zombie flesh'. While they succeeded in gaining great resilience, it ultimately caused degeneration. Now they're desperate for every morsel of hellerium-tainted flesh, zombie or otherwise. At least that much we can divine from their barely articulate ramblings. Let it be a lesson to us, because, really, they're useless for anything else.