Mark is one of the three protagonists of the story. He is the “echo maker” whose brain injury changes the status quo for everyone else. Karin and Weber try to interact with Mark only to find their approaches bouncing off him. They react by beginning to echo his condition. Karin starts to wonder whether she is the “real” Karin, and Weber begins to see himself as a fraud.

Mark’s is a coming-of-age story. He is nearly 30 years old but is immature for his years. His friendships are based on video games and reckless play, which leads to his accident. His dead-end job offers no prospects for change or growth. Part of Mark’s immaturity stems from Karin sheltering him. As a child, Mark benefited from Karin’s protection, as she shielded him from the worst abuses of their erratic parents. However, she also prevented him from coming of age, and he remains a perpetual child.

Mark’s accident is a symbolic death. He realizes this when he first starts the olanzapine treatment and tells Karin he died on the operating table and has been walking around dead ever since. He lives metaphorically in the underworld while he learns to let go of all the stories he has been trying to tell himself.