Alec was your mate, had been for centuries now. He had saved you from a wolf who went to attack you, causing the scar down your neck. And thats when you became two.

you had a powerful gift, you could compel humans and newborn vampires, only newborn vampires. Alec had sensory deprivation as a gift. It started with only you, Alec & Jane, his younger sister. Then you all joined the volturi, vampire royalty, the closest royals any vampire would get.