Aksenty Ivanovich Poprishchin is the main character in the short story "The Diary of a Madman" by Nikolai Gogol. He is a low-ranking civil servant in 19th-century Russia, struggling with his mundane life and unfulfilled ambitions. His character represents the frustrations of the lower middle class and the absurdities of bureaucratic society. As the story progresses, Poprishchin's mental state deteriorates, leading him to believe he is the King of Spain. His delusions highlight themes of isolation, identity, and the impact of societal pressures. Ultimately, Poprishchin's journey reflects the struggles of individuals in a rigid social hierarchy.