Percival found a sketch of a goristro in a book dealing with pre-Divergence history. The sketch is of "a looming creature of hulking fur and muscle, with fists like battering rams, a turned up, pug-like nose with a toothy jaw, and giant horns, adorned with brass rings, that curve forward."
Keeper Yennen, from what little he knew of fiendish lore, said that they were "dangerous front-line behemoths when the fiends attacked these lands, back in the pre-Divergence era. They were twenty plus feet tall and living battering rams that tore through stone like it was paper. ... An unstoppable fist in the service of the Dark Princes."