Bethany is the reincarnation of Bathymaas, though for millennia she had no memory of that life. Yet she used to return to the fishing spot where she met Aricles and it was there that she re-encountered him as Styxx. She was in her human form because she was searching for Apostolos and couldn't hunt openly in the territory of the Greek pantheon. The gods are blind when they take human form, so she could not see what Styxx really looked like. If she could, she would have recognized him as the prince of Didymos. However, he lied to her and posed as a peasant, fearing that she would use or reject him if she knew the truth. Thus she repeatedly attacked him on the battlefield because he commanded an army attacking Atlantis and she was the Atlantean goddess of wrath. She eventually learned of Styxx's identity and told him that she was Set's daughter, but did not tell him she was a goddess. She had planned to give up her godhood and live as a mortal with him, but just before their wedding, Apollymi obliterated the entire Atlantean pantheon. The only mercy she granted was to remove their unborn child from Bethany's womb and place him in the womb of Stryker's second wife.
Bethany and the other Atlantean gods existed as non-sentient statues in Katoteros for eleven thousand years, until Simi accidentally woke them while searching for Bethany. Bethany did not wake because both halves of her heart were missing. Set had removed and hidden one half after Aricles died and Bathymaas went on a vengeful rampage; the other half died and was reborn with Styxx. Leto had stolen Set's half and used this to summon Bathymaas and trick her into killing Styxx. When Styxx was reborn yet again with his Chthonian powers, the couple was finally reunited and Bethany was whole. Their second son was born nine months later.
In Invision, there is more to the story of Bathymaas than what Set had told. Bathymaas was not just a gift from the Source to him. She sprang from the death of Rubati, the wife of the first Malachai, from his grief which is why she was a shell with no heart. Monakribos said she was his promise of a plague of unending misery on the earth, that the gods would not have peace or love or happiness until the day they do right by him and make amends for what they had wrongfully stolen. This plays into the present day in Chronicles of Nick because Nekoda is Bethany's daughter from the future. Kody is Rubati reborn because Styxx gave Bethany/Bathymaas back her heart. It is why Kody is Nick's anchor.
- Invision, page 326