Are Tian Heng and Zhang San the same person in the Eight Wastes of Ghost Valley?

No, according to the information of official website, the game "Eight Wastes in Ghost Valley" is a role-playing game developed by Ghost Valley Studio. Hengtian was the patriarch of Taishang Daozong and was killed by the elders. Zhang San is the NPC in the game, and one of the Taoist friends that players meet in the game. He is not alone.