The woman who is potentially behind Katheren, if it turns out to be true in a twisted sort of way, she is the one who knows the Traveler the best. (aside from Paimon) Most of our daily interactions both minor and major go thru Katheren and by extension her. Who wants to bet she has a Yandere like obsession with the Traveler? And has a terrifying amount of personal Knowledge on them and obsesses over their many accomplishments?