Corask was an archaeologist who led the Obroan Institute for Archaeology team on Rafa IV. This was the time when the Toka had transformed back into the Sharu and researchers flocked to the planet to discover the information about the ancient times. One piece of technology sought after was the Sharu life crystals. When Sris Lehhett convinced the Sharu to trade the crystals, he provided workers to harvest them. However, the workers were little more than slaves, used for their life energies. Appalled by this, Corask planned to eliminate key Sharu who were in league with Sris Lehhett. When his plan was discovered, he was placed onto one of the crystal orchards. A rescue team soon arrived and was able to free him. He then was able to destroy the orchards with the help of the rescue team.