He is the Volsces' preeminent military hero. Like Coriolanus, his identity is closely tied to his fame as a warrior. The two men share a long-standing rivalry; their personal combat in I.viii represents the fifth time they have met on a battlefield. Though their hatred of each other is intense, so is their mutual admiration. As many commentators have pointed out, Aufidius's speech at IV.v.101-35—when he discovers that his uninvited guest is Coriolanus—has strong elements of homoeroticism. "Let me twine / Mine arms about that body" (IV.v.106-07), cries Aufidius. The sight of Coriolanus makes him happier, Aufidius says, than he was when he saw his bride crossing the threshold on their wedding day.
Though Aufidius's attitude changes when Coriolanus becomes the popular favorite of the Volscian soldiers, he shows profound insight into Coriolanus's character. In a conversation with his lieutenant in IV.vii, he notes that Coriolanus is uncomfortable when people praise him—that it makes him uneasy. Aufidius suggests several reasons to explain what led to Coriolanus's banishment: his pride, a "defect of judgment" (IV.vii.39), or his temperament that served him supremely well as a warrior but that would be fatal in a political leader. Commentators have suggested that the reason Aufidius understands Coriolanus so well is because they are so much alike.
In many ways, however, Aufidius is very different from his rival. He's a pragmatist and a clever analyzer of circumstances. He's willing to affect an attitude of continued good will toward Coriolanus even while he waits for the right moment to undermine him. And he's prepared to use any means—whether they're honorable or not—to accomplish his goal. Aufidius seems to have no qualms about manipulating Coriolanus or about using the Volscian people to carry out his personal revenge. He knows just which charges will most incite Coriolanus into a rage—"traitor" and "boy"—and he employs them brilliantly in the play's final scene. The conspirators who have joined Aufidius in the plot against Coriolanus kill the Roman, and Aufidius arrogantly plants his foot on the corpse—until one of the Volscian lords orders him to remove it.
Aufidius may be sincere when he begins his eulogy of Coriolanus by saying "My rage is gone; / And I am struck with sorrow" (V.vi.146-47). Since he has frequently acknowledged Coriolanus's superiority and found fault only with what Coriolanus did, not what he was, Aufidius's declaration that "he shall have a noble memory" (V.vi.153) seems to ring true. There is justice in Aufidius's charge that Coriolanus betrayed his Volscian allies. But his scornful claim that Coriolanus was moved to spare Rome because of "a few drops of women's" tears (V.vi.45) reveals more about Aufidius's small-mindedness than it does about Coriolanus's character.