Ah, I never got around to beating the Black Goat in Chaos Dungeon or the Lake God for that matter. Thanks, I'll check that out.Small correction. If you get the lore from the skull in the chaos dungeon after fighting Baphomet. We find out that the Black Trial was founded by one of her children/twins to be specific. Which are called Nug & Yeb by the skull.
I believe Mary Sue made her own garden for BS1 since we see that it separately identifies her garden as Lost Empire, Elysium. So I don't think she took over TCO's garden. I think she just had the opportunity to steal Grimm back.-BS1/Mary Sue took the oppurturnity when TCO went mad/out of controle to take over the Wonderland garden. She gained a foothold because of Black Rabbits prayer.