Rune is a young witch living in the New Republic, a society where magic users are actively hunted and executed. By day, she maintains a carefully crafted public facade as a wealthy, shallow socialite who supports the witch-hunting regime. By night, she operates under the vigilante alter-ego of the Crimson Moth, using her resources and gathered intelligence to smuggle condemned witches to safety. She is driven by intense guilt over being forced to turn in her own grandmother to the authorities.

Gideon is a captain in the Blood Guard, renowned for his role in dismantling the previous Reign of Witches. He views magic users with intense hatred due to a traumatic past that left him physically and emotionally scarred. Dedicated to his duty, he begins pretending to court Rune Winters to investigate his suspicion that she is the Crimson Moth, though he struggles with his genuine feelings for her.

Alex is Gideon's younger brother and Rune's most trusted confidant. Unlike his brother, Alex is a compassionate supporter of witches who secretly serves as the getaway driver for the Crimson Moth's heists. He harbors deep affection for Rune and consistently prioritizes her safety, even when it puts him at odds with the Republic's laws.

Cressida is a deceased royal from the former Reign of Witches. During her time in power, she took Gideon as a lover but subjected him to cruel punishments and horrific abuse when he attempted to leave her. Her sadistic actions directly caused the deaths of Gideon's family members, sparking the rebellion that overthrew the witch queens.

Verity is a scholarship student at the capital university and Rune's close friend. She acts as the Crimson Moth's second-in-command, helping Rune concoct spells and plan daring prison breaks. She is highly dedicated to their cause and often appears exhausted from her demanding schedule.

Seraphine is a powerful witch who spent nearly two decades in exile before being captured by Gideon Sharpe. She is a former close friend of Rune's grandmother, making her rescue a deeply personal priority for the Crimson Moth.

Harrow is a sharp-eyed informant who works closely with Gideon Sharpe. She gathers intelligence from the docks and local taverns, eventually discovering a link between Rune Winters's cargo ship and a recent escape of twin witches.

Laila is a witch hunter in the Blood Guard and a prison warden. She is highly dedicated to the New Republic's cause and frequently participates in raids, guard duties, and public purgings alongside Gideon.

Known as the Good Commander, Nicholas Creed is the leader of the New Republic. Following the revolution, he instituted the Red Peace regime to eradicate witches. He previously helped a young Gideon learn how to box and channel his anger productively.

Nan was Rune's beloved grandmother and guardian who raised her after her parents died in a shipwreck. She was a witch whose execution haunts Rune, driving the young woman to become the Crimson Moth as a form of lifelong penance.

Noah is a wealthy peer of Rune's who circulates in the same elite social circles. He inadvertently provides Rune with valuable information regarding Blood Guard activities through casual conversation.

Tessa was the younger sister of Gideon and Alex. She died tragically from a fatal sweating sickness induced by Cressida Roseblood as a cruel punishment for Gideon's failure to meet the witch's demands.

Lizbeth is the sole staff member employed at Wintersea House. She handles daily affairs, delivers telegrams, and maintains the household while remaining discreet about her employer's activities.

Octavia is the wife of the Good Commander. She maintains an office at the Oakhaven Park estate where she keeps detailed maps of the prison layout that become a target for the Crimson Moth.