|“||I will not cross the Dark Lady.||”|
Serephone roams around in Tartarus with Kelli and three other empousai. She distrusts Kelli along with other empousai. When they attack Percy and Annabeth, Annabeth tricks the empousai into believing that Kelli was useless and weak and that she was leading them all into danger. Annabeth tells them to follow Serephone as she was older and wiser. Hearing this made Serephone happy and declared that she was a leader. Kelli became angry and killed Serephone.
She is loyal to Hecate, calling her "The Dark Lady", and was willing to turn away from Gaea when she discovers that Hecate has made peace with Olympus. She showed a strong distrust of Kelli and was open-minded enough to consider Annabeth's words when Annabeth told her about Hecate's alliance with Olympus. She is reasonably ambitious as she wanted to be a leader, and was respected enough by her sisters that she was able to break up a fight, and had the backing to threaten to depose Kelli, should she lead them poorly.
Serephone is an empousa, who are the servants of the goddess Hecate. It is unknown what she looks like but due to her being an empousa, it can be assumed that she has the features of an empousa which is that in true form, she has completely white skin, flaming hair, fangs, one bronze leg and one donkey leg, and red eyes. While in her mortal form, she is very beautiful as Chiron says that the power of deception of an empousa is very great as almost any male hero can fall under their spell and be devoured.
- Seduction: As an Empousa, she can put men under her spell so she can feast on their blood.
- Charmspeak: As an Empousa, she can charmspeak in order to attract her mortal victims.
- Shapeshifting: As an Empousa, she can change from her human form to their true form.
- Mist Manipulation: As an Empousa, she can manipulate the Mist.
- She never actually was seen charmspeaking anyone, but she has the power because she is an empousa.