1. Max (Maxwell Kane): The narrator and protagonist, a large, clumsy boy with a troubled past and a learning disability. He struggles with social situations and often feels inadequate.
2. Freak (Kevin Avery): A small, brilliant boy with a rare form of dwarfism. He is fiercely independent and uses his intelligence and wit to overcome his physical limitations.
3. The Grim Reaper: A terrifying and mysterious character who is said to roam the streets and kidnap children. Max fears him deeply.
4. Tony: Max's older brother, who is physically imposing and often bullies Max. He is disrespectful towards his family and struggles with anger issues.
5. Gram: Max's grandmother, who loves him unconditionally and offers him comfort and support. She provides a stable and loving presence in his life.
6. The Killer's Dad: A dangerous man who threatens Max and Freak. He is a violent and unpredictable figure who instills fear in the community.
7. Blade: Tony's friend, a tough and intimidating bully who often joins Tony in tormenting Max.
8. The Fair Gwen: A kind and sympathetic neighbor who is a friend to both Max and Freak. She is a calming presence in their lives.
9. The Teacher: Max's teacher, who initially struggles to understand him. She later shows patience and compassion, helping him to learn and progress.
10. The Principal: The stern and unsympathetic principal of Max's school, who is quick to punish him for his misbehavior.