- "Do you trust the face you see in your reflection? I don't."
As the younger twin sister of Eritha, the high priestess of Aphrodite, Diona felt overshadowed by her sister. She joined the Cult as a way to gather power and overthrow her sister.
Sometime during the 420s BCE, Diona made the acquaintance of the Spartan misthios Kassandra. Seeing her as an opportunity she instructed Kassandra to complete several tasks, including; freeing mercenaries, returning stolen poison, and killing a captain. Under the guise of being a victim of the Cult, Diona successfully deceived Kassandra into delivering exactly what she needed to fulfill her coup.
With her obstacles out of the way, Diona made her way to the Altar of Aphrodite in order to kill her sister. Kassandra managed to catch up with her and learned that Diona and Eritha were identical twins, having only previously spoken to Eritha through a door. Using this, Diona attempted to trick Kassandra into killing Eritha instead of her, but after a brief moment of confusion, Kassandra saw through Diona's lies and killed her.
- Diona is an optionally-romancable character.