The Grabber is a cruel, mentally unstable, sadistic serial killer who appeared to obtain enjoyment in the psychological torment of his victims. This can be seen in the ways he subjects them to a myriad of sadistic games after abducting and imprisoning his victims in his basement. He was also shown to be wrathful as well as fixated on wearing his masks whenever he engaged in his acts, which is demonstrated during his drastic loss of composure upon Finney removing his mask. However, when he is wearing different parts of his interchangeable mask, he seems to have other personalities of sorts.

Max was The Grabber's younger brother who came to stay at his house, presumably after losing his own in Durango, Colorado. He admitted to being between jobs, and it was likely that his cocaine addiction caused a spiral leading to his loss of career and residence. Max called The Grabber to request if he could temporarily reside in their childhood home, and his brother agreed, despite having Finney Blake locked in the basement.

He was born sometime in 1965 as the first and only son of Terrence Blake and his wife Hope Blake and later became the older brother of Gwen Blake in 1967 when he was 2. While walking home from school one day, Finn is abducted. His kidnapper is the infamous Grabber, a local serial killer. Locked in his soundproof basement, Finn uses a phone to communicate with the Grabber's deceased victims, who insist on making sure Finn escapes alive. Simultaneously, Gwen searches for him through the use of her prophetic dreams.

Gwen is the younger sister of Finney, who helps defend him from his bullies in school yards. Gwen has psychic powers and can see ghosts and different past and future events in her dreams. Gwen and Finney's father is very abusive and doesn't support her with her dreams, saying "they're just dreams."

Vance Hopper is a quintessential tough guy and a local school bully known for his volatile and aggressive nature. He is a ruffian who has a reputation for getting into trouble and brutally hurting people, leading to multiple arrests. Described as the strongest student in the school before his disappearance, his personality is defined by his readiness for a physical fight and a standoffish demeanor, rarely showing vulnerability. Despite this rough exterior, his spirit later manifests to help Finney, offering guidance on how to fight back against their captor.

Robin was a boy of Mexican descent who lived in Denver, Colorado, where he met and became friends with Finney Blake. Sometime before 1976, he lost his father in the Vietnam War. He was great at martial arts and would often spend time with his uncle, going to the drive-in to watch movies.

Bruce was born in the United States and was raised by a Japanese born father, Mr. Yamada, and mother. At some point, he moved to North Denver, USA. as a child, he developed his love of baseball and his bond with his parents, before being abducted and murdered by The Grabber. Bruce also had a younger sister named Amy, who was a classmate of Finney's sister Gwen.

Sometime in 1975 while delivering newspapers, Billy was abducted by The Grabber and taken to a soundproof basement. During his captivity, he tried to use a rope to reach the basement window, however, he likely failed to open it. Afterwards, he hid his rope in a hole in the wall. At some point, he fell into The Grabber's trap and left through the half-open door left by him, once up there, Billy was beaten until he passed out. Soon after, Billy was tortured and murdered by him. After his death, his soul remained in the basement of his captivity.

In 1976, Griffin was abducted by The Grabber and placed in his soundproof basement. During his captivity, he scratched the combination to his bicycle lock on the wall using a bottle cap. He would later fall into the Naughty Boy game set up by The Grabber. Like the others, he would have found the door ajar, climbed the stairs, and been viciously beaten by the man's belt. Griffin was subsequently murdered by a knife to the throat, and his ghost remained in The Grabber's basement.