Paige is a 19-year-old Irish clairvoyant, specifically a "dreamwalker," living in the authoritarian city of Scion London. Her rare ability to enter other humans' dreamscapes makes her highly valuable to the underground criminal syndicate. After her arrest for killing two security guards, she is transported to an Oxford penal colony where she is forced into servitude under the Rephaim race. She is defiant, intensely private, and fiercely loyal to her marginalized community, secretly seeking ways to return to her former life.

Warden, also known as Arcturus, is a Rephaite who serves as the "blood-consort" to Nashira. He operates as Paige's keeper and trainer in Oxford, subjecting her to an intense and strictly regimented instruction process. Despite his authoritative position, he shows occasional flashes of protectiveness. He harbors his own private agenda regarding the future of the captive voyants and the battle against the monstrous Emim creatures.

Nashira is the elegant and merciless "blood-sovereign" of the Rephaim. She commands strict obedience from both her own race and the captive humans in Oxford. She possesses vampiric qualities, feeding on the auras of talented voyants to increase her own power and bind spirits to her command. She specifically desires a dreamwalker and takes a menacing, proprietary interest in Paige.

Nick is a doctor-in-training and a voyant who serves as Paige's first real connection to the underground clairvoyant community. He saves her from a vicious spirit attack during her youth and introduces her to Jaxon Hall's syndicate. He is observant, kind, and provides Paige with a much-needed sense of safety and medical care in a hostile society.

Jaxon, often called Jax, is a "mime-lord" who runs a criminal gang in London's clairvoyant underworld. He acts as Paige's protector and employer, utilizing her rare dreamwalking abilities to maintain security over his enterprise. He is an opportunistic businessman who values loyalty strictly when it aligns with his own financial and territorial interests.

Liss is a soothsayer relegated to the squalid "Rookery" district in Oxford. She uses a tarot deck as her physical connection to the spiritual aether. As a "harlie" who refuses to swear allegiance to the Rephaim, she survives by performing contortionist acts for her captors. Pragmatic and compassionate, she quickly becomes Paige's primary source of information regarding the rules of Sheol I.

Julian is a captive seer who undergoes brutal physical training in Oxford. Banished to the harsh conditions of the Rookery, he endures regular beatings from his Rephaite keeper. Despite his mistreatment, he maintains a defiant spirit and seeks ways to organize the human captives against their oppressors.

David is an Oracle assigned to serve the Rephaite Overseer. He holds a privileged "pink shirt" position compared to the harlies but secretly despises the Rephaim and their brainwashing tactics. He quietly passes crucial information to Paige.

Seb is a young amaurotic—a human without clairvoyant abilities—who has been wrongfully incarcerated in Sheol I. He suffers severe physical abuse at the hands of the Rephaim guards and represents the extreme cruelty of the Rephaite regime.

Finn is Paige's older cousin from Ireland. As an activist who actively protests the oppressive Scion government, he instills a sense of political defiance in Paige from a very young age.

Zeke is a newly recruited voyant with an unusually unreadable dreamscape. He works for Jaxon Hall's syndicate alongside his sister, catching Nick's romantic attention.

Nadine is a voyant recruited by Jaxon Hall. She displays a defiant attitude that creates immediate friction with her new crime-lord employer.

Eliza is a trance medium employed by Jaxon Hall. She assists the mime-lord with his ongoing research into clairvoyant classifications.

Pleione is a Rephaite who conducts the orientation for captive voyants in Sheol I. She possesses eerie yellow eyes and strictly enforces order, using deadly psychic force to silence human protests.

Aldura is a Rephaite keeper assigned to train Julian. She employs brutal physical methods and forcefully defends Nashira's interests during Paige's testing.

Michael is Warden's amaurotic servant at the Magdalen residence. He works quietly under Rephaite rule, passing discreet messages and supplies when instructed.

Nuala is a tame deer illegally kept by Warden within the city limits of Oxford. She provides company for Warden and serves as an unwilling subject for Paige's possession training.

Danica is the "resident genius" of Jaxon Hall's criminal syndicate in London. She assists with the technical monitoring of the ethereal plane and scolds Paige for mistakes.

Haymarket Hector serves as the Underlord of the Syndicate. He enforces rules among the various criminal gangs in London and accuses Jaxon's crew of cheating.

Tilda is a captive voyant, specifically a "whisperer," living in Sheol I. She self-medicates with an addictive substance called aster to cope with the trauma of her captivity.

Suhail is an aggressive Rephaite enforcer. He issues violent threats to captive humans who break curfew and forcefully drags Paige to Nashira's chambers.

Kathryn is a red-jacket, a human voyant who serves as a security officer for the Rephaim. She enforces Rephaite rules against her fellow humans and cruelly destroys Liss's tarot cards.

Antoinette Carter is a leader of an Irish dissident group resisting the Scion government. The Rephaim actively hunt her, assigning red-jackets to capture her during a secret meeting with the syndicate.