Norman Bates is the titular main protagonist of the Psycho franchise. He is a serial killer who suffers from psychosis and Dissociative Identity Disorder, believing himself to be his controlling mother. At the same time, he suffered from visual and auditory hallucinations, in which his mother apparently talked him into committing acts of violence in order to appease her.

When the Mother personality took over, Bates would fly into murderous rages targeting women who aroused him, usually whilst dressed in her clothing. He is known to have eventually slaughtered his mother and kept her mummified corpse in the basement of his house for many years.

Norman's "Mother" personality is as cruel and possessive as the real Norma had been in life, frequently berating him and forbidding him to have a life outside of her. As "Mother", he dresses in Norma's clothes and talks to himself in her voice, and he also speaks to her corpse as if it is alive. "Mother" also kills women whom Norman feels attracted to, and anyone else who threatens the illusion of her existence. Norman passes out when "Mother" takes control; after "Mother" commits a murder, Norman awakens and destroys the evidence, convinced that "she" alone is responsible for the crime.