The Traveller (alternatively, the voyager/explorer, from German, der Forschungsreisende) is a man of reputation and putative wisdom. He visits the penal colony to witness the torture of the Condemned Man performed under the command of the Officer. He is initially restless and irritated by the blazing heat, but then becomes interested in the Officer's explanation. Invited by the New Commandant to ostensibly condemn the apparatus and practice, the Traveller is beseeched by the Officer to intercede and speak in his favor. The Traveller's choice not to do so leads the Officer to condemn himself.
The Soldier guards the Condemned Man and is thus a part of the system that ensures such men face a torturous death. However, though he is essentially a henchman to the Officer, he seems to befriend the Condemned Man; the two of them do not speak French and have clownish personalities. He desires to leave the penal colony but the Traveller refuses to take him.
The Condemned Man
The Condemned Man is a prisoner who has been charged with failing to honor his superior, but he was not given a defense and does not know he is already considered guilty. He thus waits for a punishment and a death he does not expect, and is intrigued by the apparatus before he knows what it is going to do. He is described as a rather stupid and brutish figure prone to clowning and infantile joking. He is saved when the Officer decides to kill himself instead.
The Officer is a fastidious and dedicated figure. He is excessively loyal to the Old Commandant and to the apparatus, and wants the Traveller to help him continue his torturous executions. When the Traveller refuses to help him by reporting well to the Commandment, the Officer decides to torture himself instead. This means he saves the Condemned Man in a rather ironic, messianic way, but the Officer's plans go awry when the machine brutally kills him instead of letting him enjoy the religious experience that the drawn-out torture should bring to him.
The Old Commandant
The Old Commandant ran the penal colony in the past and created the apparatus; he is described as a veritable renaissance man. He inspired much devotion and the apparatus and its system of justice were quite popular under his rule. However, after the Old Commandant's death, his views and practices fell out of favor and he was looked upon as a brute. He was refused burial in the cemetery and his devoted followers, who later went into hiding, could only secure a gravestone near the tea house. The Officer is fiercely devoted to the Old Commandant's vision.
The New Commandant
This man is in charge of the penal colony and seems keen on breaking with the Old Commandant's more archaic and brutal methods of keeping order and punishing wrongdoing. He has a coterie of women who are always with him and advise him, and he putatively invited the Traveller to the colony to condemn the apparatus.
In the Penal Colony Questions and Answers
The Question and Answer section for In the Penal Colony is a great
resource to ask questions, find answers, and discuss the novel.