In book 12 of the Aeneid, Ternus demands that the terms of single combat with Aeneas be set. The next morning, both armies line up and people watch from Latium's walls to see the fight. Still defying fate, Juno urges Ternus'sister, Jeterna, to save him from death. Making offerings before the duel, Aeneas vows to deal honorable with the Italians win or lose. But it's obvious that Ternus is no match for Aeneas.
Jeterna, herself a minor goddess, begins to rile up the Ruchulians, showing them a sign, many smaller birds driving away a fierce eagle. When a Ruchulian throws a spear, the truce starts to fall apart. Aeneas tries to stop the fighting, but he's hit by an arrow and has to retreat.
This gives Ternus hope, and he starts to rampage in his chariot. Just like that, the war resumes. Venus helps heal Aeneas, and he strides into battle, looking for Ternus.
Terrified, Jeterna impersonates Ternus'chariot driver to keep him away from Aeneas. Both roam the battlefield, killing enemies. Prompted by Venus... Aeneas attacks the city and threatens to burn it.
Thinking Ternus is dead, the queen hangs herself. When Ternus learns his city is falling apart, he returns to fight Aeneas, stopping the battle. In single combat, Ternus'sword breaks as he mistakenly grabbed his charioteer's inferior blade.
He runs from Aeneas until Jeterna delivers his own sword. Juno finally stops fighting Aeneas'fate, asking only that his descendants be called Latins, not Trojans. Jupiter calls off Jeterna with an omen, one of the Furies in the form of an owl, which also harasses Ternus.
After Aeneas wounds Ternus in the leg, he asks for mercy for his father's sake. Moved, Aeneas is inclined to grant it. That is, until he sees Pallas'sword belt hanging on Ternus'shoulder.
Enraged, he stabs Ternus in the heart, finally killing his rival. After many delays and diversions, Aeneas and Ternus have finally come face to face in single combat. Through Aeneas, the destiny of Rome is preserved.
Roman piety encompasses not just reverence for the gods, but also for country and family. And that runs as an undercurrent through this last book of the poem. Aeneas'piety to the gods is explicit in his offerings and prayers before single combat is set to begin. On the other side, Ternus may believe he will preserve his family and country by winning, but he will not be. but he fails to consider the very real, readers know, inevitable possibility that he will lose, bereaving his father and perhaps destabilizing his country.
It is unclear whether Virgil intended to end the poem so abruptly. It doesn't fit the pattern of other epic poems, which usually conclude with sections that wrap up the details of the story. Virgil died before finishing the epic, but if the ending we have here is what he actually intended, it makes his denunciation of war war and the grief it causes, evoked by Ternus'sad ghost in the last lines of the poem, a very powerful one.