That's a tough one. Different ghost stories have different actors playing the ghost. You might need to provide more details about the particular story for a precise answer.
I don't have that information off the top of my head. Maybe you could tell me more about the ghost story, like the title or where it was shown, and then I could try to help you figure out who played the ghost.
Often, the other ghost might be a forgotten soul from the past, seeking redemption or closure. Maybe it's a character whose story wasn't properly told in life and is now revealed in the ghostly realm. Another possibility is a ghost that represents a collective fear or trauma of a community.
The real person in Sister Ghost's ghost story was not a specific character but a legendary ghost image. In different novels, stories, movies, and TV shows, the image of Sister Ghost might have different descriptions and explanations, but it was usually considered a terrifying, mysterious, and supernatural existence.
At present, the identity of the ghost in the inspection yard in "Celebrating Years" had not been clearly revealed. There were some clues that suggested that Yan Ruohai might be a mole, but there were also other clues that pointed to Zhu Ge. Chen Pingping and Yan Ruohai conspired to plot a double act in an attempt to confuse the others. However, the exact identity of the mole had yet to be revealed. Therefore, it was impossible to determine the identity of the ghost in the inspection hall.