I don't remember where, maybe in the Mary Sue's ending, but she said that they meet before and she didsn't like Nyarlathotep(I'm assuming it's the crawling one).
I thought that Player Master was a fairy tale that sold Grimm to Mary Sue to survive.
We already know that the fairy tales in the Lost Empire are twisted by Mary Sue. They was made to make Grimm the hero of the story. Maybe in BS2 was how they original were.
I'm kind of expecting that in BS3 we will meet Mary Sue's mom and we will know more about what fairy tales are. I'm curious about why some enemies in BS1 doesn't have a book and why some books are different in color in BS2(aside from the fact they aren't technically fairy tale)
Doesn't really rule out the possibility that Mary Sue kinda of tried to use Nya for her own gain in the past imo, betrayal might be her trademark
Prayer Master originally is the black rabbit of the Tea Party Trio (Alice, Black Rabbit, and newcomer), when newcomer (literally Grimm) and Alice (Nyarlathotep) fell in love Black Rabbit prayed to the gods and his wish fulfilled, the two are seperated in the form of BS1. He did sold them to Mary Sue, but for different reason
I'm kinda skeptical at whether BS2 fairytalrs are stories originally written by Grimm or something else (like story depicts the character's real life before dragged into the Outer God's mess)
For Mary Sue mother, though, she is Bahomet aka Shub-Niggurath, Mabel (Yog-Sothoth)'s wife. We yeeted her at the end of BS1, and tbh I could only think of Node and Prickett as Grimm's possible allies in BS3, Yog-Sothoth would likely stay neutral and other Outer Gods would just mess Grimm up, he experienced that, like, at least twice already.