Three Sisters - Act 3 Side Quest
Start Location: Qiyun Ascent/Jinghe Wetlands
Quest Location: Jinghe Wetlands
Objective: Clear the Tigermen camp in eastern Jinghe Wetlands and speak with Ru Zhao
Three Sisters is the final Side Quest in Act 3 and can be started multiple different ways. The most common method is by speaking with Yi Shan in Qiyun Ascent (pictured above). You'll typically pass by Yi Shan on your way to the Jade Palace for the story mission, if you don't speak with Yi Shan to start the quest then you can speak to her sister Li Hua in Jinghe Wetlands instead.
All of this quest takes place in Jinghe Wetlands despite the quest giver being in Qiyun Ascent. You'll pass through the wetlands after talking to the Jade Emperor and leaving through the back exit of the Jade Palace; alternatively from Chang'an go through the door and out the southwest exit to get to Jinghe Wetlands. This door will be closed until after you complete Journey to the Jade Palace at which point you can open it.
For this quest you will need to free Ru Zhao from the tiger encampment in eastern Jinghe Wetlands. There will be a pack of tigers guarding her and typically one is a Hero enemy but they should be easy enough for you. Talk to Ru Zhao multiple times to update the quest then head over to Li Hua in the central portion of the Jinghe Wetlands to turn in the quest. Map locations of both these NPCs are shown below.