Years ago, Kresh was the most feared creature in the city-state of Dorn. His cunning, natural abilities, and talent made him the best assassin in any of the scattered cities. It was only after several failed attempts that the city council managed to trap Kresh and neutralized the threat he posed by placing a powerful forget spell on him. Some memories must have remained though, since he was still a devout follower of Tiamat and zealously urged people to convert for her return.
While the PCs were beneath the streets of the city, something happened, and Kresh became whole again. He followed the group down and tried to make them his triumphant return to the top of the underworld. While inflicting serious damage, he was unable to accomplish his goal and was forced to flee. The PCs have not seen him since.