She is just a dream of Sankawa Granny!
As for why Meijia is here, the reason is not complicated. As I said before, Shenyue and the Bai Fan family's great-great-grandfather set three rules, and these rules are useful.
First, only the birthday star lives on the east side because the old house is sealed on the east side, and this area is the domain where Shenyue devours dreams. Moreover, this ability does not differentiate between friends and foes, so at that time, it won't be just the birthday star whose dreams are eaten.
The reason for going to the chapel after staying for a night is mainly to stabilize one's mind. After all, after being devoured by dreams, most people will become mentally unstable. Essentially, it's like losing SAN value without knowing it, but as long as it's not discovered, the loss won't be too much.
For someone as oblivious as Blondie, who slept through till daylight, he probably would only lose 1 or 2 points at most.
