Gus –
Gus is a submissive junior hit man who is constantly bossed around by Ben. Both Gus and Ben are protagonists of the play, but the audience, also limited in knowledge, sees the play from Gus's point-of-view, and empathizes more with him. Gus is more sensitive, has a conscience about his job, and is bored by the stale routine of his lower-class life. He also questions the inner workings of their job more, especially with regards to the mysterious Wilson.
Ben –
Ben is the senior hit man, the dominant foil to his submissive partner Gus. He runs their outfit, but pays strict attention to the demands of Wilson, their boss. He often broods silently, reads the newspaper, doesn't question their job, and evades Gus's probing questions.