Who was Forbes in the book monster?

You're likely thinking of Forbes, the monster from the book "Monster" by Walter Dean Myers.

In the book, Forbes is not a person, but a gang. It's referred to as a "monster" because it represents a brutal, violent, and fearsome force in the community where the protagonist, Steve Harmon, lives.

The book doesn't focus on any specific individuals in the gang, but rather on the impact the gang has on Steve's life and the wider community.