The Traveller
The Traveller (alternatively, the voyager/explorer, from German, der Forschungsreisende) is a man with a high reputation from an unspecified foreign country. He visits the penal colony and is asked by the New Commandant 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. The Traveller is beseeched by the Officer to intercede and speak in favor of the apparatus. The Traveller's choice not to do so leads the Officer to torture and kill himself.
The Soldier
The Soldier guards the Condemned Man and is thus a part of the system that ensures such men face a torturous death. Though he is essentially a henchman to the Officer, he seems to befriend the Condemned Man. He has a simple, clownish personality. He desires to leave the penal colony at the end of the story, 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. Since he was not given an explanation or chance to defend himself in a trial, he does not know what is happening to him at the beginning of the story. He thus is intrigued by, rather than fearful of, the apparatus. 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
The Officer is a fastidious and dedicated figure. He is excessively loyal to the Old Commandant and to the apparatus, and he wants the Traveller to help him continue his torturous executions. When the Traveller refuses to stay silent about his distaste for the apparatus, the Officer decides to torture and kill himself instead. This means he saves the Condemned Man in a rather ironic, messianic way. The apparatus brutally kills him instead of letting him enjoy the religious experience that he believes drawn-out torture brings.
The Old Commandant
The Old Commandant, long gone by the time the story takes place, ran the penal colony in the past and created the apparatus. He is described as having been an intelligent, multi-talented 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 harsh leader, his methods deemed archaic. He was refused burial in the cemetery and his devoted followers, who later went into hiding, could only secure a gravestone near the penal colony's tea house. The Officer is fiercely devoted to the Old Commandant's vision.
The New Commandant
The New Commandant 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. The Officer believes that The New Commandant invited the Traveller to see the apparatus so that he will condemn it and give the New Commandant reason to abolish its use.
The Captain
Like the Old Commandant and the New Commandant, the Captain does not actually appear in the short story but is referenced by the Officer. The Condemned Man was the Captain's servant, and he was supposed to keep vigil outside the Captain's door and stand and salute every hour when the clock struck. The Captain sent the Condemned Man to be killed for failing to wake up one night when the clock struck 2 o'clock.
