spoilers from the novel-
ok so someone said that in the novel it was later explained that her mother was actually a temporary “saintess” and she was only supposed to fill the spot until the real saintess aka. our fl came however fl’s mother got greedy and she wanted the power to be all hers so she got help from the ‘darkness’ that will later kill her and destroy the world in the first life after fl and ml die. so basically the fate of being saintess was never hers but she loved the power to she basically restored herself anywho when the fl gets her powers later the ‘darkness’ discards the mother and kills her because she becomes useless
Well at least this world doesnt judge by looks, because mama dearest sure doesnt look at all saintly yet they all believed her