Aaron's guess had been right.
The bloodstained divine coin pointed toward Tarathia because Six-Fingers was using some secret method to have his daughter replace Waukeen, the goddess of wealth.
The process had already begun.
From Tarathia's memories, Aaron finally learned the whole story, including why the goddess had been imprisoned in Six-Fingers' domain.
This was what had happened:
After the Time of Troubles began, the theft of the Tablets of Fate so enraged the Overgod Ao that he cast every deity down into the mortal world. He forced them to roam Realmspace in avatar form, forbidding them from returning to their Divine Realms until the Tablets of Fate were recovered.
During that chaotic era, the gods had all focused on their own affairs. Some seized the chance to eliminate rivals and strike at enemies, some busied themselves searching for the Tablets of Fate, and others enjoyed the rare pleasure of wandering the mortal world, such as Silvanus, the Father of Oaks, and Tymora.
Unlike those gods, Waukeen, the Lady of Wealth, wanted nothing to do with any of it. All she wanted was to return to her Divine Realm in the Astral Plane, the Eternal Marketplace. To that end, she traveled with Lliira, the goddess of joy.
Waukeen knew about the Infinite Staircase in Shadowdale. The two goddesses initially intended to return to their Divine Realms that way, but unfortunately, the Overgod Ao had anticipated this. Helm, the God of Guardians, stood watch over the staircase. With his divine enforcer privileges activated, Helm was invincible against anyone below the Overgod. The Second Goddess of Magic had fallen because of him.
Seeing that this plan would not work, Waukeen tried a different approach.
She intended to turn herself into a commodity and have herself shipped out of the Prime Material Plane.