+ Adam
- Private investigator, morally ambiguous.
- Motivation: Money, desperation.
- Arc: Starts as cynical, becomes desperate and vulnerable.
- Relationship: Antagonistic with Lawrence initially, forms a bond through shared suffering.
+ Lawrence Gordon
- Doctor, flawed family man.
- Motivation: Saving his family, surviving.
- Arc: Forced to confront his neglectful behavior.
- Relationship: Strained with his wife and daughter, forced to cooperate with Adam.
+ Jigsaw (John Kramer)
- Former civil engineer, cancer patient.
- Motivation: 'Rehabilitating' people by forcing them to value life.
- Arc: From cancer patient to vengeful punisher.
- Relationship: Appears detached, views his victims as flawed individuals needing correction.
+ Detective Tapp
- Obsessed with catching Jigsaw.
- Motivation: Justice, revenge for his partner.
- Arc: Driven to madness by the case.
- Relationship: Antagonistic towards Jigsaw, protective of his partner Sing.