In Virgil's Aeneid, Turnus is the antagonist to Aeneas. Turnus is a Rutulian prince who violently opposes the Trojan settlement in his region of Latium. He is also a passionate fellow who is madly in love (or lust) with Lavinia (whom Aeneas marries). Turnus, of course, is furious that his rival takes his woman and settles in his land, and his furor drives him out of control and clouds his judgment. He is violent to the point of corruption, and he acts rashly, blinded by his passions and mostly without a sense of justice or morality.
Scholars debate which characters in Homer may serve as a model of Turnus. Some point to the Trojan prince Hector, who fights the Greeks when Achilles is absent. Turnus fights the Trojans when Aeneas is absent. Others argue that Paris might serve as a model, for Paris, too, is driven largely by his passions. After all, he takes Helen and starts a major war. This is certainly a rash act, and it has significant consequences.
Still other scholars think that Achilles is the primary Homeric model for Turnus. This makes sense, for Achilles's rage in battle is a sight to behold, but he is also rather fickle, refusing to fight for a while when he is offended (because he loses a woman). He allows his passions to control him both in battle and out. Achilles's morals are also quite questionable. After killing Hector, for instance, Achilles will not allow the prince to be buried but rather drags the prince's body around Troy for days out of revenge. The gods finally have to step in to stop this extreme insult. We can see, then, that Achilles and Turnus actually have quite a bit in common, not the least of which is their violent hatred for the Trojans.