Unnamed Parents (Deceased)
In "Karl", before Karl's arrest, it is explained that to commit his murders, Karl used painting as a ruse. In prison, Karl continues his ways until most of the inmates and guards die from the virus. Eventually, Karl kills the only remaining guard Martinez, when he threatens to leave. His attempts to escape the prison fail and as a last resort, Karl plans to commit suicide, but before he can do so, Phil and Todd discover him.
Karl pretends to be a prison guard in "Paint Misbehavin'" to the group, when Phil and Todd bring him back to the mansion. Phil begins to suspect something wrong with Karl and he later discovers him consuming Gail's band-aid and witnessing Karl dig up a corpse to eat pieces of it with Todd. Karl reveals his cannibalistic ways to the group in "Hamilton/Berg". When locking him back up in the prison fails, the group decides they must execute him, but before Phil can go through with the execution, a bomb planted in a Rubik's cube kills Karl.
A funeral for Karl is held in "Señor Clean".
He is portrayed by Fred Armisen.