The Underground Man
The Underground Man is self-loathing, embittered, and reclusive. He cannot or will not conform to society's norms, and he rails against the social principles of rigid rational egoism in the 1860s and the inauthentic and absurd romanticism of the 1840s. His acute consciousness of his alienation causes him immense suffering, but somehow he welcomes the suffering as a mark of his independence from and rejection of society.
Liza
Liza is straightforward and has an honest soul. She falls under the spell of the Underground Man's "game" in which he ostensibly tries to "save" her from prostitution but in reality is trying to humiliate her. She visits the Underground Man and reveals she loves him, but he can respond only with disdain and cruelty intended to destroy her.
Officer
The officer becomes an object of the Underground Man's revenge for the simple reason he brushed against him without noticing him. The Underground Man takes this as an unforgivable insult and concocts an elaborate plan to get revenge and restore his honor.
Apollon
Apollon is a calm and self-assured man whose natural self-confidence makes the insecure Underground Man furious and vengeful. The Underground Man uses petty actions to demean Apollon, who has disdain for his master's pathetic need for superiority.
Simonov
Simonov is a fairly mature, levelheaded young man who dislikes the Underground Man and his need for superiority. He tries to be reasonable with the Underground Man, but the latter finally tries his patience to the limit. It is at Simonov's apartment the Underground Man invites himself to the dinner being planned.
Zverkov
Zverkov is the guest of honor at the farewell dinner the Underground Man intrudes upon. Zverkov seems to be friendly, charming, and handsome, with good manners. He tries to engage the Underground Man in conversation but is rebuffed. When the Underground Man humiliates himself at the dinner he imagines challenging Zverkov to a duel to regain his honor.