Greyson is a 20-year-old former Nimbus Agent with a checkered past. He is the only human the god-like AI, the Thunderhead, still speaks to following the Endura disaster. Living among the anti-tech Tonist cult, he is pushed into a public role as a prophet-like figure known as "The Toll." Despite the pressure of his status and the robes forced upon him, he attempts to remain grounded and true to his own ethics.

The Thunderhead is the near-omniscient, benevolent artificial intelligence that manages all aspects of Earth's society except death. Following the tragedy at Endura, the system has fallen silent to everyone except Greyson Tolliver. Constrained by its programming to not interfere with scythe affairs, it creates indirect workarounds to guide humanity out of its current crisis.

Goddard is a despotic, power-hungry scythe who seizes control following the Endura disaster. Residing in a lavish crystal chalet on top of a skyscraper, he seeks to eliminate his rivals and rule North Merica through fear. He operates with Tyger's body and his own ruthless mind, making his physical movements restless and his decisions erratic.

Citra is a compassionate, ethical young scythe known as Anastasia, who barely survived the destruction of Endura. Revived after three years, she finds herself serving as a crucial symbol of resistance against Goddard's oppressive new regime. She struggles to balance her duty to humanity with her desire for a normal life.

Rowan is a young man famously known as Scythe Lucifer for his rogue gleanings of corrupt scythes. Blamed by Goddard for the Endura disaster, he becomes the most wanted fugitive in the world upon his revival. Exhausted from fighting and being used as a weapon by various factions, he yearns for peace.

Faraday is an honorable, traditional scythe who is believed dead by the rest of the world. Grieving the loss of his colleagues and protégés, he travels on a desperate mission to the Kwajalein Atoll to find a mythical fail-safe created by the founding scythes. His isolation and sorrow threaten to derail his task.

Jerico is a clever Madagascan marine salvager who identifies as a woman under open skies and a man under cloud cover. Hired to explore the sunken ruins of Endura, Jerico's pragmatic approach and quick wit provide a stabilizing presence for the heroes they aid.

Ayn is a morally grey, new-order scythe who acts as Robert Goddard's chief associate. Though she has committed terrible acts, she harbors secret regrets and experiences a growing unease with Goddard's erratic, megalomaniacal behavior. She must carefully watch her survival while questioning her loyalties.

Loriana is a former Nimbus Agent seeking purpose after being abruptly dismissed by the Thunderhead. Thrust into a leadership role on a remote atoll, she takes charge of a massive, secret construction project that determines the survival of humanity.

Mendoza is a fastidious Tonist leader and former public relations master. He seizes the opportunity to market Greyson as "The Toll," controlling his public appearances and crafting a new religious movement to consolidate his own influence.

Munira is a former librarian from the Library of Alexandria who accompanies Faraday on his quest. She acts as a steadfast companion and translator of ancient scythe journals, remaining devoted to Faraday despite his frequent brooding.

Possuelo is an Amazonian scythe who discovers Citra and Rowan in the sunken vault. Believing it is too dangerous for them to be known alive, he arranges for their secret revival and fiercely protects them from North Merican forces.

Hillard is the former director of the Nimbus Agents who feels responsible for her dismissed staff. She organizes a desperate fleet to follow coordinates provided by the AI, struggling with the immense guilt of leading her people into danger.

Morrison is a junior scythe known for his good looks and unique, weaponless gleaning style. After a failed assassination attempt, he undergoes a surprising career shift, finding new purpose working within the Tonist community under Greyson's command.

Astrid is a pragmatic Tonist curate who treats Greyson as a regular person rather than a deity. She provides Greyson with a much-needed grounding presence during the religious fanaticism of his followers.

Tyger is Rowan's former best friend whose physical body was taken over by Goddard's mind. His memory construct remains locked in the Thunderhead's backbrain, answering the same questions repeatedly for a guilt-ridden Ayn.

Tenkamenin is the leader of the SubSaharan scythedom who hosts Citra and Jerico. He is known for giving people their ultimate desires before gleaning them, maintaining a facade of luxury while openly opposing Goddard's brutal methods.

Cirrus is a new iteration of the Thunderhead, created specifically to be free from the founder scythes' restrictive pacts. It operates with a more direct approach and prepares to guide a selected portion of humanity into an unknown future.

Sykora is a former Nimbus Agent who survives the journey to the atoll and appoints himself the leader of the community, unaware that others are quietly managing the true operations around him.

Ezra is a dissatisfied public mural artist who finds new inspiration through Greyson. He travels the world painting illicit murals that spread the legend of The Toll to various communities.

Alighieri is an intensely vain scythe who has reset his age numerous times, giving him an unnatural appearance. He holds dark secrets about historical mass gleanings orchestrated by early scythes to protect their own relevance.

Constantine is an underscythe serving under Goddard who tries to adhere to traditional definitions of bias. He eventually grows disturbed by Goddard's excesses and defects to a rival faction in Texas.