Chelsea and Jane try to break Bella's shield, but it doesn't work. Bella's shield even withstands Alec's powers.
Seeing the anger and confusion in the Volturi's faces, Bella realizes that they might have a chance to win against the Volturi if she can incapacitate their offensive forces.
I would be the number one priority, the first one to die, but as long as I held, we were on more than equal footing with the Volturi. (38.38)
As the Cullens and their witnesses divide up their respective enemies among themselves, Aro makes a last offer to the gifted vampires on the Cullen side to join the ranks of the Volturi. Thanks, but no thanks.
The brothers vote. Markus and Caius are divided, so the decision to fight is left to Aro. He restates his concern that he gladly would leave in peace if he could be absolutely sure that Renesmee will not pose a danger for the future.
As if on cue, Alice unexpectedly returns with Jasper, and with three other vampires in tow. Alice introduces one of the strangers, a young man, as Nahuel. It turns out he's a half-human, half-vampire hybrid, just like Renesmee. Unfortunately, his human mother died while giving birth.
Nahuel reveals that he has three sisters, and that his vampire father is planning on producing more hybrids to create a super race. Although Nahuel is venomous, his sisters, like Renesmee, are not. He also explains that he reached maturity seven years after his birth, and that he hasn't changed since.
Nahuel's evidence prompts the Volturi to drop their charges and to instead go after Nahuel's father to stop him. They leave.
The Cullens and their friends erupt in cheers. Bella is overcome with joy at the turn of events:
Happiness expanded it like an explosion inside me – so extreme, so violent that I wasn't sure I'd survive it. (38.172)