Sifting Through Void

There's no rubble on the surface. The beasts are burrowing, so they must be finding it in a cavern underground. I've been thinking of how to get there. You've noticed the vortexes that dot the Storm Fields? They twist space, moving things from place to place. Step through one and I can reveal the anomalous residue that surrounds them. Collect the residue and I can make a spell to redirect the portal to where the source of the rubble is!