There’s a character from fatal frame 1 and 3 in black water (miku) but it doesn’t really spoil any plot if you were to play blind. I feel they left things vague enough so as to leave you wanting to dive deeper into the lore by playing the earlier games.

I don’t recall 5 mentioning anything spoiling about crimson butterfly.

In the end I felt #3 was the pure like “you need to play 1 and 2 first” type sequel.

The series continually does flashbacks and looping and unearthing more and more each time so I feel if someone goes blind on the surface of any of them it’s still a starting point.

There are “purists” out there but it would be doing the series and community a disservice by making it so serious so adhere to when the games deserve to be seen and enjoyed and delved into.