Rosella Cullen is no ordinary vampire. For starters, she drinks animal blood. Secondly, she was born, raised and changed in Italy, but not by the Volturi. Thirdly, she is older than all of the Cullens. Fourthly, Rosella is an immortal child, frozen forever at 14.
Rosella is the "youngest" of the Cullen family, and despite being over a hundred years older than Carlisle himself, Rosella still acts like a child most of the time. Also, while she feeds from animals like her family, Rosella's eyes maintain their newborn ruby gleam.
Danielle is an immortal child. Those who have read or watched Twilight, know immortal children are illegal in the vampire world. On the penalty of death. But Danielle is a very special immortal child with a powerful gift of compulsion and remarkable self-control. She has been a vampire for a hundred years and has gone undetected by others of her kind. As well as keep existences of vampires a secret. But that changes when she settles down in Forks and meets the Cullens. Warning: very slow updates