After Karl is arrested and all of the prison inmates and guards die from the virus. Karl and guard Martinez begin to bond as they are the only two left. Martinez explains that he stuck around because everyone he once knew is dead. When Martinez tells Karl that it is his last day, he gives him two months worth of food and a noose to kill himself. Karl begs him to let him but he says Karl is dangerous and the latter shakes his hand to say goodbye but pulls him in and kills him to escape his cell but cannot escape the prison.
When Karl laters plans to commit suicide, he apologizes for killing him and says goodbye to Martinez's grave.
He was portrayed by Geoffrey Rivas.