Pervases is a Yaksha who perished a thousand years ago. We first meet him in Xiao’s Story chapter 1: A Butterfly’s Dream. Even though Pervases is long gone, the traveler would like to rebuild his temple and give him some offerings.
To begin the quest, teleport to the Liyue Harbor and go to the Wanmin Restaurant. Talk to Chef Mao to order 3 pieces of Grilled Tiger Fish. Why? This is because Pervases previously said that he misses the taste of the Grilled Tiger Fish.
After getting the Grilled Tiger Fish, use the Teleport Waypoint to the west of Liyue. Go to the quest area, where you will meet Xiao near the abandoned temple. Talk to Xiao and you will hear someone asking for help.
Follow the quest area and defeat the enemies surrounding Wang Ping’an. Talk to Wang Ping’an and go back to the abandoned temple.
Wang Ping’an will examine the abandoned temple saying that it is in a dire state.
After talking to Wang Ping’an and making sure he is genuine, you will be able to complete the Hereafter: The Trail of Pervases questline.