Medusa is a seventeen-year-old mortal girl living on an isolated island with her divine parents and immortal sisters. She teaches herself to read multiple languages from scrolls that wash ashore and dreams of exploring the world beyond her home. Possessing brown skin, wide-set eyes, and lush locs, she often feels isolated as the only mortal in her family. She maintains a strong sense of justice that puts her at odds with the patriarchal demands of her father and the unpredictable temperament of her mother.

Stheno is Medusa's twenty-one-year-old immortal sister. She is plain-spoken and highly pragmatic, possessing a clear understanding of how dangerous their world can be. She observes the cruelty of potential suitors and gods alike, using her sharp instincts to protect her younger sisters from harm.

Euryale is Medusa's nineteen-year-old immortal sister. Desperate to escape the oppressive environment of her parents' island, she views an arranged marriage as her only viable exit strategy. She is highly emotive and deeply loving toward her sisters, willing to endure mistreatment from suitors if it guarantees her freedom from her father's control.

Athena is the Olympian goddess of wisdom and Zeus's favorite daughter. She appears as an elegant woman with braided red hair and gray eyes, projecting an aura of justice that masks her true ruthlessness. She recruits acolytes to serve in her temple in Athens, demanding absolute chastity and obedience while punishing any women who fall short of her rigid standards.

Poseidon is the Olympian god of the sea and ruler of the watery courts. He possesses striking beauty, sun-bronzed skin, and immense charisma. He carefully orchestrates his encounters to isolate his targets, using emotional manipulation and feigned vulnerability to gain their trust before asserting his brutal dominance.

Appolonia is an acolyte at Athena's temple who hails from a wealthy, high-born Athenian family. She possesses golden skin and graceful movements that remind others of the goddess herself. She maintains a strong commitment to non-violence and acts as a gentle, steadying presence during the rigorous temple trials.

Theo is an enslaved worker at Phorcys's palace. He has curly black hair and a grounded personality tied closely to his work with the earth. He dreams of leaving the isolated island to experience the broader world and acts as a clear-eyed voice of conscience, refusing to be blinded by the glamour of the visiting gods.

Phorcys is a primordial sea deity and the father of Medusa. Once a mighty king, he has lost most of his power to the Olympian gods. He compensates for his diminished political status by ruling his household as a tyrant, enacting physical violence upon his wife and using his daughters as property to secure alliances.

Ceto is a primordial sea goddess and Medusa's mother. She harbors immense grief over the loss of her older children, whom the Olympian gods deemed monsters and took away. She frequently lashes out at her daughters in displaced anger but actively attempts to warn them about the true, dangerous nature of the gods who rule their world.

Maheer is the demi-god son of Ares and a wealthy prince. He uses his royal status to hide his vicious temper, casually brutalizing his servants and enforcing his will through intimidation. He views marriage purely as an acquisition of property.

Kallisto is a blonde, fair-skinned acolyte serving at the temple of Athena. She comes from a privileged background and actively bullies those she considers beneath her, using cruelty and intimidation to assert dominance over the other young women in the temple.

Euphraxia is a high priestess in her sixties at the temple of Athena. She oversees the rigorous training, testing, and daily chores of the acolytes. She strictly enforces the temple's rigid moral codes and quickly dispenses severe punishments to any woman who breaks them.

Amphitrite is the daughter of the old sea god Nereus and the wife of Poseidon. She shares physical similarities with Medusa, including brown skin and lush locs. She was aggressively pursued by Poseidon and now endures a loveless marriage marked by his constant infidelities.

Kallinikos is a charioteer competing in the Panathenaia festival. Believing himself to be the underdog in the races, he asks Medusa to offer prayers to Athena on his behalf to secure a victory.

Amersa is one of the few acolytes who advances to the final stages of priestess training at the temple of Athena. She acts as a passive observer to the conflicts between the other young women.