OG Jade & Tabitha did evil act.
Someone posted how they believed that Jade and Tabitha might’ve been the ones who did the sacrifice and it got me to thinking how the BIW told Christopher information which made him crazy, what else would drive someone mad besides immense guilt?
I think they tried to sacrifice their children or something nefarious and now their souls are trying to undo it. Or something wants revenge for what they did. Maybe the MIY is a child they sacrificed and he’s getting revenge.
Im starting to have doubt about the validity of their flashbacks because it could be what they want to remember. Maybe the monsters weren’t the ones sacrificing which would explain their modern clothes, they were turned the same way Fatima was.