Katherine is a 17th-century woman executed for witchcraft who now wanders Black Spring as a physical ghost. Her most defining features are her eyes and mouth, which have been tightly sewn shut by the town's historical founders. She serves as a silent, unnerving presence whose proximity dictates the town's oppressive laws and heavy surveillance.

Steve is a medical professional and rationalist trying to raise a family in a town governed by superstition and fear. He accepts Black Spring's strict, authoritarian rules as a pragmatic necessity to keep his loved ones safe. He struggles to bridge the gap between his scientific worldview and the supernatural reality of his home.

Jocelyn is a former geologist and dedicated mother who attempts to shield her family from the psychological toll of Black Spring. She uses domestic pragmatism to cope with the terror of living alongside a supernatural entity. Her primary focus is maintaining a semblance of normalcy for her sons in an inherently abnormal environment.

Tyler is a 17-year-old aspiring vlogger who resents the oppressive, fear-based culture of Black Spring. He leads a secret group of teenagers in conducting experiments on Katherine to test the boundaries of the curse. He hopes to eventually expose the town's secret to the outside world, driven largely by a desire to be honest with his girlfriend.

Jaydon is a 19-year-old resident with a volatile temper and a history of domestic trauma. He harbors intense hatred toward Katherine, blaming her for his abusive father's disappearance. He frequently escalates the teen group's pranks into genuine acts of cruelty against the witch.

Grim is the cynical head of HEX, the high-tech organization responsible for tracking Katherine and maintaining the town's absolute quarantine. He relies on cameras, smartphone apps, and theatrical deception to manage the supernatural threat. He despises his job but views it as a necessary defense mechanism for the community.

Matt is the 13-year-old son of Steve and Jocelyn. He enjoys horseback riding and generally acts like a typical young teenager. Underneath his typical adolescent exterior, he has deeply internalized the town's superstitions and folklore regarding the witch.

Griselda owns the local butcher shop and serves on the Town Council. A survivor of severe domestic abuse, she has developed a secret, obsessive reverence for Katherine van Wyler. She privately leaves offerings for the witch in the woods, believing Katherine protects her.

Mathers is the head of the Town Council and the primary political authority in Black Spring. Deeply religious and puritanical, he favors harsh historical punishments over Grim's modern security methods. He actively manipulates the town's fear to maintain strict control over the populace.

Lawrence is a teenager in Black Spring and a core member of Tyler's "Open Your Eyes" project. Like Tyler, he wishes to test the limits of the town's curse through modern documentation. He is observant and occasionally serves as the voice of reason when experiments go too far.

Burak is a local teenager involved in the "Open Your Eyes" group. While initially drawn to Tyler's pseudo-scientific approach to the witch, he is highly impressionable. He easily falls under the sway of Jaydon's more aggressive and chaotic methodology.

Justin is a friend of Tyler's who assists in documenting the witch. He treats the curse as a subject for juvenile pranks and viral videos. Like Burak, his sense of camaraderie eventually leads him to participate in darker activities spearheaded by Jaydon.

Pete is a sociologist and the Grants' neighbor. He acts as the town's unofficial historian, explaining the origins of Black Spring and the horrific execution of Katherine van Wyler. He advocates for a measured, democratic approach during town crises.

Mary is Pete's wife and Lawrence's mother. She is a supportive presence in the neighborhood, reflecting the tight-knit but anxious social fabric of Black Spring.

Burt is a newcomer from New York City who purchases a home in Black Spring. He is initially completely ignorant of the town's supernatural reality until a terrifying encounter forces him to realize he is permanently trapped.

Bammy relocates to Black Spring with her husband, Burt. She represents the horror of an outsider violently inducted into the town's inescapable quarantine.

Arthur is a resident imprisoned by the town for continuously breaking the rules of secrecy. He is kept hidden from the outside world and supplied with food by Griselda Holst.

Warren works in the HEX control center monitoring the surveillance feeds. He helps analyze footage of Katherine's movements and coordinates with the rest of the security staff.

Claire is a HEX employee tasked with tracking Katherine's location via the town's extensive camera network. She ensures the witch's presence is logged and managed effectively.

Marty is a HEX officer who becomes increasingly unnerved as supernatural phenomena escalate. He favors aggressive, militaristic responses to the town's crises over observation.

Lucy is part of the staff that manages the day-to-day surveillance of Black Spring under Robert Grim's command.

Adrian is a HEX staffer who acts as an operator for the Town Council, utilizing the organization's surveillance footage for political and punitive purposes.

John is a highly superstitious town resident who actively incites panic and demands severe retribution to appease the curse.

Laurie is an outsider unaware of the supernatural horror governing Black Spring. She serves as Tyler's primary motivation for wanting to expose the truth about his life.

Milford is Jocelyn's father. Because he lives outside Black Spring, he is completely ignorant of the curse and the true reasons behind the tragedies afflicting his daughter's family.

Joey is a young boy in Black Spring who becomes intertwined with Katherine's wanderings as the town's social structure breaks down.

Naomi is Joey's sister, a small child living in the increasingly chaotic town of Black Spring.

Fletcher is the Grant family dog. His sharp instincts make him highly reactive to the supernatural presence of the witch, which eventually puts him directly in her path.