Lyra is the newly crowned Queen of the Underworld and a former mortal thief cursed by Zeus to be unlovable. Having recently won the Crucible Games and godhood, she is violently separated from Hades when dragged into the underworld prison of Tartarus. Resourceful, fierce, and deeply loyal, she must survive the Labyrinth's psychological trials without her weapons or new divine powers.

The King of the Gods and ruler of the Underworld. Feared for his deadly powers and a prophecy stating he will destroy the world, he is fiercely devoted to Lyra. His separation from her drives him to destructive extremes as he tries to breach the impenetrable gates of Tartarus from the outside.

The mythical King of the Titans, imprisoned in Tartarus after the ancient Titanomachy. Known in legend as a brutal tyrant who devoured his own children, he is a formidable and menacing presence in the Underworld's dungeon. He drops Lyra into the first trial, viewing her as a key to the Titans' escape.

Lyra's loyal best friend and former partner in the Order of Thieves. Recently resurrected and named the new god of thieves, he is dragged into Tartarus alongside Lyra. Pragmatic and highly skeptical, he relies on his thief skills and survival instincts to protect Lyra in the treacherous prison.

The Queen of the Titans and Hades's mother. Imprisoned in Tartarus, she is characterized by her serene demeanor and silver eyes. She acts as a calming, protective presence among the volatile Titans, offering shelter and guidance to Lyra and Boone when dangerous forces sweep through the tunnels.

The goddess of spring, whose imprisonment in Tartarus was the original catalyst for Lyra's actions in the Crucible Games. Bright and cheerful, she moves through the dangerous environment of the prison using her plant-based powers, though her motives and past interactions create tension within the group.

One of the Titans imprisoned in Tartarus. Impatient and aggressive regarding the Titans' escape, he favors throwing Lyra directly into the Labyrinth's dangerous challenges to force her to unseal the Locks.

The Titaness of prophecy who shares imprisonment with her family in Tartarus. Her foresight drives the Titans' belief that Lyra's arrival is crucial to their long-awaited escape from the underworld dungeon.

The masked Titaness of memory trapped in Tartarus. She tracks the history of the Titans' imprisonment and the unusual temporal anomalies occurring within the labyrinth.

A Titaness trapped in Tartarus who falls victim to the unseen threats known as the Pandemonium, demonstrating the severe psychological dangers of the prison by transforming into a feral state.

A Titan imprisoned in Tartarus, known for his analytical mind. He is one of the few permitted into the strategic planning sessions for navigating the Labyrinth's Locks.

The goddess of home and hearth, presumed dead in previous wars. She appears as a magical recording or projection serving as the guardian of the Labyrinth's first psychological test, the Lock of innocence.

Lyra's estranged father. He manifests as part of a magical glamour designed to grant Lyra her deepest, unfulfilled childhood desire for a loving and accepting family.

Lyra's estranged mother, who abandoned her to the Order of Thieves at a young age. She appears within the Labyrinth's illusions to test Lyra's emotional vulnerabilities.

Lyra's former boss in the Order of Thieves in San Francisco. He appears within the Labyrinth's first Lock as part of a fabricated reality designed to test Lyra's desires.

The King of the Olympian gods. He originally cursed Lyra to be unlovable, setting her difficult life in motion. He is seen in temporal visions leading the Olympian forces during the ancient Titanomachy.

A Titan who avoided imprisonment in Tartarus. Lyra views his actions in the past through temporal anomalies, raising questions about his current whereabouts.

An Olympian goddess who intervenes to stop Hades from fulfilling a destructive prophecy. She later serves as the symbolic guardian of one of the Labyrinth's psychological Locks.

The multi-headed guardian hound of the Underworld. He assists in physically restraining a furious Hades to prevent him from destroying the realm in his desperation to reach Lyra.

The ferryman of the Underworld. He attempts to appeal to Hades's better nature, reminding him of Lyra's wishes in order to prevent catastrophic destruction.

The Egyptian god of death. He acts as a formidable authority figure among the global pantheons, threatening severe consequences if Hades continues his destructive attempts to breach Tartarus.

A formerly cursed mortal, now trapped mysteriously within the walls of the Labyrinth. She shares information with those who find her, carrying a deep hatred for the gods who wronged her.

A former rival pledge from the Order of Thieves who ruthlessly bullied Lyra in her youth. He manifests as a psychological obstacle in one of the Labyrinth's trials.