Jerhyn is the young ruler of Lut Gholein, and apparently the son of a sultan. Having been advised by Drognan and Fara to trust the heroes arriving from the west, he welcomes them to his fair port city. Overall reaction to his rule seems mixed to positive, with some questioning his ability to lead, but with many others insisting that he will become a fine sultan in his time.
At the beginning of Act II, he's hiding the fact that his palace is being overrun by demons from below. An unnamed Vizjerei mage (only known as The Summoner, later on) had discovered the entrance to Horazon's Arcane Sanctuary underneath the palace, and had secretly opened it and entered, leaving the demons bound within free to enter the palace through the gate. They slaughtered the town's prostitutes, who had been granted shelter within the palace, and were only barely kept in check by the full efforts of the palace guards. This losing battle in the palace was the reason that Jerhyn had hired Greiz and his mercenaries to guard the city. He did not tell any outsiders what was going on until the player character had made sufficient impression on him that he let them enter the palace and the Sanctuary.