In the books she is born from Hecate, not from a water nymph. But she also says she is a sorcerer, so she might know more magic then just transformation. She says that men are pigs and probably feels that more after the pirates destroy her spa. But maybe Andrew could spare her instead of killing her and could make her feel less hateful to men.
also what do you think of this idea?
When Nico and Andrew shadow travel from Circe’s island, they land in New Orleans as Nico says he felt a strong presence as Anubis is fond of New Orleans, particularly its way of sending off the deceased. Because of this, while he is in charge of the Hall of Judgment, a New Orleans graveyard is linked to it. Nico almost finds the entrance when he and Andrew get pulled into a shadow to the start of the sword of Hades. The pantheons don’t want to interact unless they have to like a world ending event.