The Devil Within

A 30-year-old man with a disability tormented by lifelong nightmares who becomes haunted by a speaking mirror and the demon called the Cadaver. He communicates with his reflection, and the reflection gradually asserts control, driving him toward deadly acts. His backstory as a child prodigy, later overshadowed by a traumatic incident, fuels guilt and confusion as to what is real.

Dennis’s brother who bears the burden of caring for him while grappling with his own secrets and guilt. He resents social services’ intervention yet remains protective, revealing a complicated moral landscape. His relationship with Lydia and his confrontation with Dennis’s crimes push him toward desperation.

John's girlfriend who pushes for marriage and external stability, offering reluctant support and emotional conflict. She encounters Dennis, faces fear after a violent incident, and ultimately reacts to the escalating danger as the situation spirals out of control.

A social services worker who believes Dennis needs removal from the home, triggering a clash with John over responsibility. Her visit foreshadows the institutional responses that fail to counter the growing danger.

Dennis’s crush who works at the ice cream shop and met an awkward, rejected moment with him. Her rejection contributes to Dennis’s volatile behavior, and her death marks a turning point in the story.

John’s friend who unveils critical tapes and ultimately helps surface the truth about Dennis’s past, warning of looming danger as the investigation closes in.

A living demon that fastens onto Dennis and uses the reflection as a channel to inhabit and control him, conducting a spree of killings. The entity embodies the film’s horror core, blurring the lines between demon, mirror, and mind.