Showing a calm and confident personality most of the time, Fyodor doesn't appear to fear to his enemies, boasting enough courage to let himself be captured by them. Despite being extremely arrogant, he is a straightforward and intelligent man with a truly sinister personality.

He refers to himself as carrying out the lord’s will and always talks about the sinful nature of man. Ironically, Dazai names him "Demon", saying he had met Fyodor only once in the past.