Jove calls a council of the gods on Mount Olympus. He reminds the gods that he commanded that Italy and Troy should not fight, and asked why they've ignored his orders and what has caused the war. Venus responds first, describing the Trojans' great suffering, Turnus's pride, Allecto's troublemaking, and more. She begs Jove at least to save Ascanius, saying he can do whatever he wants with Aeneas. She proposes that the Trojans return home to rebuild Troy.
Venus's willingness to throw Aeneas under the bus seems bizarre, but it might actually show her faith in fate. She knows he'll have to survive to found the city, so she can pretend not to care about him to strike a better bargain.
Juno angrily responds that Aeneas chose to make Turnus his enemy, and that he brought war to a peaceful land. She says that Jove could have helped Aeneas more if he'd wanted, though she acknowledges that he twice saved the Trojan ships. She finishes by saying that Jove's anti-war complaints come too late.
While Venus is a canny bargainer, Juno is simply a liar. The council humorously reflects political meetings in the Rome of Virgil's day, when different rhetoricians would attempt to convince the public by whatever means necessary.
Jove rules that the war should proceed, since there's no other solution. The war's results will be left to fate.
Fate is more powerful than the gods—or at least more powerful than all the gods other than Jove—but of course Jove's being unrealistic if he thinks Juno and Venus won't meddle further.
Back on earth, as the battle rages on, Aeneas continues to search for allies. He finds Tuscans (also called Etruscans), whose king, Tarchon, along with many Tuscan warriors, sail back to Latium. As Aeneas steers his ship in the night, the nymphs that his other ships transformed into in Book 9 swim up to him. The nymph Cymodocea describes the battle situation back in Latium, encourages Aeneas to fight well, and speeds up the boats.
Just after Jove's declaration that the war should be left to fate, Aeneas gets some divine help from his former ships. Perhaps Jove has factored divine intervention in as part of fate—the gods can help in the specifics, but can't change the larger outcome.
Aeneas and the Tuscan troops arrive at the battle in the morning, and Aeneas's Vulcan-made shield shines impressively. Turnus rallies his men to fight on the beach with the famous line: "Fortune speeds the bold!" The fighting begins and Aeneas successfully kills many men, though Achates, his trusty friend, is injured.
Despite Turnus's words, it's not clear that fortune (i.e. fate) favors the bold. Fortune is impartial, and would seem random if it weren't all pre-ordained. This is another subtle suggestion that Turnus might not deserve his doom. His courage makes him a hero in his own right.
Pallas, the young son of Aeneas's ally Evander, sees some of his men, the Arcadians, fleeing in fear on their horses, and gives them a heartening speech. Pallas rushes into battle and his men follow. Pallas fights with Lausus, a boy his age, the son of Turnus's important ally Mezentius. Fate has determined that neither will return to their homes.
Pallas is brave and thoughtful to his men, but, as with Turnus, those good traits can't change his fate. The foreshadowing puts us readers in the position of the gods. We know and mourn what will happen to Pallas before he does.
Turnus's sister Juturna tells him to go help Lausus. Turnus tells the soldiers crowded around to back off so he can kill Pallas, and says he wishes Pallas's father were there to see. Pallas bravely responds that his father will be able to handle any outcome.
Turnus acts like a real villain here. His savagery and total lack of piety for the father-son bond echoes Pyrrhus, the Greek who killed the Trojan king Priam's son before Priam.
Pallas prays to Hercules, who watches from the heavens and groans that he can't help. Jove comforts Hercules, saying that the fates are unchangeable, but human bravery brings lasting glory. Pallas throws his spear but barely nicks Turnus. Turnus tauntingly says that he might be able to do better than that, then throws his spear and hits Pallas right in the chest. As Pallas dies, Turnus says that he'll get a proper tomb. Turnus takes Pallas's belt as a prize. Virgil foreshadows that in the future Turnus will wish he'd never touched Pallas.
Jove's words recall Nisus and Euryalus's deaths as well. As we've seen, much of the second half of the Aeneid focuses on giving the brave their deserved praise. Turnus continues in villain-mode, taunting Pallas until he makes the kill. But then his promise to bury Pallas properly shows that he respects the Trojans and the rules of war.
When Aeneas hears of Pallas's death, he goes into a killing frenzy. He takes several Latins alive to use as human sacrifices at Pallas's funeral, then continues to slaughter his enemies. Aeneas even kills men who beg for mercy, insults the corpse of one of his victims, and makes fun of another after he's already killed him. Ascanius and other Trojans finally appear at the battle.
As Turnus becomes more respectful, Aeneas becomes something of a monster, again echoing Pyrrhus, and foreshadowing the poem's end. His lack of pity goes against the Roman traits that Anchises defined of mercy and peacefulness.
Back on Mount Olympus, Jove tells Juno that Venus has been helping the Trojans. Juno asks to remove Turnus from the battle, where the Latins are badly losing, so he can at least see his father, Daunus, before his death. Jove agrees, but warns Juno that she will not be able to use this as an excuse to change the whole war. Juno sends a phantom Aeneas down from the heavens. Turnus throws his spear at the fake Aeneas, then chases the phantom onto a boat, which Juno quickly sets sail away from the battle.
Juno's action is motivated by concern for Turnus, not just rage against the Trojans. She's slowly realizing (as Jove forces her too) that she won't be able to change fate, so instead of strengthening Turnus, she removes him from the battle so that he can fulfill the pious father-son bond. But her good intentions effectively make Turnus look like a coward.
Aeneas searches unsuccessfully for Turnus. Meanwhile, Turnus realizes he's floated away, and makes a desperate speech to the gods, unsure why he has to suffer so much, why he's doing what he's doing, and even who he is. He says that he wants to commit suicide, or to jump in the water and swim back to the battle, but Juno stops him.
Turnus's speech of desperation is a slightly crazier version of Aeneas's similar anguish and near-suicidal pessimism in Books 1 and 5. The speech shows that he's not a coward, just struggling to accept his fate and the manipulations of the gods.
In Turnus's absence, Mezentius takes over leadership of the Rutulians. Mezentius is described as resembling a cliff unaffected by crashing waves, a wild boar so ferocious that hunters are afraid to come near. Making a kill, he resembles a hungry lion feasting on his prey's blood. One of his victims, Orodes, warns in his dying words that Mezentius doesn't have long to live, but Mezentius scoffs, saying Jove protects him.
The wild, quickly-changing descriptions of Mezentius show both the excitement of war and the quick-changing character of Mezentius. Mezentius's transformations, from cliff to boar to lion, recall Turnus's transformation from murderous to calm, and Aeneas's transformation in the other direction.
Mezentius moves across the battlefield like the giant Orion, so tall that his head is in the clouds. When Aeneas catches up with Mezentius, Mezentius throws his spear at Aeneas. Aeneas deflects it with his shield, though it unfortunately kills one of Aeneas's allies. Then Aeneas throws a spear, which travels through Mezentius's shield and pierces him the groin, though it doesn't kill him.
The description of Mezentius as Orion establishes Mezentius as almost superhuman, which makes it even more impressive when Aeneas defeats him. Notice also how Aeneas shield, with its images of Rome, is so much stronger than Mezentius's shield.
Lausus cries out or his injured father, and Virgil praises Lausus's bravery as deserving lasting recognition. Lausus jumps in to protect Mezentius. Aeneas tells Lausus he's being foolish. Lausus refuses to move, and Aeneas kills him, stabbing him. When Aeneas sees the corpse, however, he grieves, thinking of his own son Ascanius, and promises to treat the body respectfully and return it to his parents.
Lausus's bravery brings him to an act of piety not even Ascanius has matched—he sacrifices himself for his father. He's on par with Nisus for his selflessness, or even Aeneas, who braved death to visit his father in the Underworld. Only the sight of dead Lausus snaps Aeneas out of his killing frenzy.
Mezentius cleans his wounds at the Tiber. When he sees the Tuscans carrying his dead son Lausus, he makes a tragic speech, acknowledging that his son's sacrifice saved him. Mezentius gets on his horse, ready to kill Aeneas or die trying. He finds Aeneas and denounces him for taking his son, and fails again and again to spear Aeneas. Finally, Aeneas throws his spear at Mezentius, killing him in one try. In his last words, Mezentius acknowledges that even his own people hate him, and asks for a proper burial with Lausus.
In a typically Virgilian move, Virgil makes us sympathize with the enemy. We know from Evander that Mezentius is an evil tyrant, and we've seen his viciousness on the battlefield. But here Mezentius shows that even he is full of love for his son and will piously sacrifice himself for him, while also acknowledging his own past cruelty.