Cullens:
In eclipse, a Newborn vampire army comes to destory Bella and the Cullens. newborns are sent by Victora {James' mate from book 1 of the sereis}. But the Cullens destory the army and all of them are safe and Bella is also.
Volturi:
The Volturi's job was to come and destory the army but the Cullens fight them off before the Volturi can get there. And then Jane { member of the guard} says that bella must be killed because she is not a vampire yet. this is soon to be contied...