Charles Milles Manson ( November 12, 1934 – November 19, 2017) was an American criminal, cult leader, and musician who led the Manson Family, a cult based in California in the late 1960s and early 1970s. Some cult members committed a series of at least nine murders at four locations in July and August 1969. In 1971, Manson was convicted of first-degree murder and conspiracy to commit murder for the deaths of seven people, including the film actress Sharon Tate. The prosecution contended that, while Manson never directly ordered the murders, his ideology constituted an overt act of conspiracy.

Azazel is a demon or evil spirit in Jewish legends and a fallen angel in Christian and Islamic traditions:  Yom Kippur In the ancient Jewish ritual of Yom Kippur, a scapegoat was sent to Azazel to carry the sins of the Jewish people. The high priest would symbolically transfer the sins to the goat, then drive it into the wilderness and cast it to its death.  Fallen angel In the Book of Enoch, Azazel is described as a fallen angel who taught humans how to make weapons and ornaments and introduced them to forbidden knowledge. 

The Leviathan is a sea serpent demon that appears in mythology and theology, and is referenced in the Hebrew Bible. It is a monstrous creature that can take the form of a dragon, snake, crocodile, whale, or primordial sea serpent. The Leviathan is thought to have originated from pre-biblical Middle Eastern mythology, especially the Ugaritic myth of Baal. 

Jeffrey Lionel Dahmer, also known as the Milwaukee Cannibal or the Milwaukee Monster, was an American serial killer and sex offender who killed and dismembered seventeen males between 1978 and 1991. Many of his later murders involved necrophilia, cannibalism, and the permanent preservation of body parts—typically all or part of the skeleton.

Dennis Lynn Rader, also known as BTK (an abbreviation he gave himself for "bind, torture, kill"), is an American serial killer who murdered at least ten people in Wichita and Park City, Kansas, between 1974 and 1991. Although Rader occasionally killed or attempted to kill men and children, he typically targeted women. His victims were often bound, sometimes with objects from their homes, and either suffocated with a plastic bag or manually strangled with a ligature.

Theodore Robert Bundy was an American serial killer who kidnapped, assaulted, and murdered dozens of young women and girls during the 1970s. After more than a decade of denials, he confessed to 30 murders. The total number of his victims is likely to be higher.

John Wayne Gacy was an American serial killer and offender who tortured, and murdered at least 33 young men and boys in Norwood Park Township, near Chicago, Illinois. He became known as "the Killer Clown" due to his public performances as a clown prior to the discovery of his crimes.