Flagg is a dark, supernatural entity occupying the form of a man. He uses the chaos of the Project Blue virus to seize power and establish a totalitarian stronghold in Las Vegas. Possessing abilities like levitation and shapeshifting, he infiltrates the dreams of the immune survivors. He specifically seeks out outcasts, criminals, and the deeply resentful to build his new society.

Abagail is a 108-year-old woman living on a farm in Nebraska. Deeply religious, she acts as a spiritual conduit for the scattered survivors of the plague, appearing in their dreams to offer a safe haven. She instructs the immune population to gather in Boulder, Colorado, to prepare for an inevitable confrontation with the forces of darkness.

Stu is a calm, observant blue-collar worker from East Texas. Because he naturally resists the Project Blue virus despite direct exposure, the military detains him in quarantine facilities for testing. After escaping, he becomes a level-headed leader for the growing community of survivors. He tries to establish a functional democracy in Boulder while preparing for the inevitable conflict with Las Vegas.

Frannie is a 21-year-old college student from Ogunquit, Maine. She discovers she is pregnant just before the plague wipes out her family and community. Practical and emotionally resilient, she buries her father herself before leaving town with Harold Lauder. Her unborn child becomes a vital symbol of hope for the entire survivor colony in Boulder.

Larry is an up-and-coming musician whose breakout hit single hits the charts right as the world ends. Fleeing debts in California, he ends up trapped in New York City during the worst of the plague. Historically selfish and prone to using people, Larry struggles to become a better, more responsible person as he forms a group of survivors and leads them west.

Nick is a deaf-mute young man who relies on written notes to communicate. Despite his physical vulnerabilities and rough past as an orphaned drifter, he possesses a strong moral core and exceptional organizational skills. As the plague empties the Arkansas town, he takes over as the de facto sheriff before following dreams of an old woman in Nebraska.

Lloyd is a petty criminal who ends up locked in an Apache County jail just as the plague wipes out the guards. Left to starve in his cell, he reaches the brink of death before Randall Flagg arrives. Grateful for his rescue, Lloyd pledges absolute loyalty to the dark man and assumes a high-ranking position in the new Las Vegas hierarchy.

Harold is an awkward, intelligent 16-year-old boy who harbors deep resentments from years of social exclusion. He is desperately in love with Frannie Goldsmith and takes charge of their early survival efforts, hoping to win her affection. When Frannie repeatedly rejects his advances, Harold's bitterness makes him highly susceptible to dark influences.

Nadine is a former schoolteacher harboring a terrible secret. Years before the plague, she received a psychic message from the dark man claiming her as his bride. She travels with a traumatized boy named Joe and eventually joins Larry's group, but she remains isolated by her belief that she is predestined to serve Flagg in Las Vegas.

Born Donald Merwin Elbert, Trashcan Man is a schizophrenic pyromaniac who spent his pre-plague life in trouble with the law for lighting fires. The dark man easily recruits him by sending dreams promising endless opportunities for destruction. He travels west to Las Vegas, guided by Flagg's supernatural interventions, to become the chief weapons scavenger for the dark army.

Glen is a retired, talkative sociology professor who travels with his fiercely loyal Irish Setter, Kojak. Immune to the plague, Glen views the apocalypse as a fascinating sociological reset. He frequently acts as the intellectual sounding board for the group, predicting how the survivors will organize themselves and warning against the pitfalls of bureaucratic power.

Tom is a good-hearted, intellectually disabled young man living in Oklahoma. He spells almost everything with the letters "M-O-O-N" and struggles with complex concepts, though he experiences moments of sharp intuition. He forms an immediate, life-saving bond with Nick Andros and travels west with him.