You have survived the open sand and the things that hunt beneath it. Maybe a haul that went wrong, maybe a station that went quiet, maybe just a long walk you should not have lived through. Whatever it was, the desert took its measure of you and let you keep the rest, and you carry the lesson in your bones: keep moving, watch the ground, and never trust still water.
Choose one of the following skill boons.
A blade cut from a Sand Reaver's tooth and a scent-fouling sand-cloak. The tooth cuts; the cloak keeps the deep sand from tasting you.
You feel the ground-tremor of a burrowing predator before it strikes, gaining advantage on awareness against ambushes in open sand, and a chance to avoid drawing the deep hunters at all.
You will not stand still on open sand. You keep moving, always.
You drink alone, back to a wall, watching the horizon.