Derlacs were large oceanic creatures, ranging up to fifteen meters in length. They lived in herds, grazing on aquatic plants and insects near the oceans of Shaum Hii. The Kian'thar herded derlacs as cattle, following them on their bentail mounts and using derlac whistles to call them. Kian'thar ranchers branded the derlacs in their herds, but otherwise let them roam around the oceans freely until it was time to bring them to market. A Kian'thar family usually took about one dozen derlacs to cattle market per year.

Derlac meat was Shaum Hii's main export.