Alec

Name             : Alec
Alias               : Witch twin (By Stefan and Vldimir)
Species           : Vampire
Perpetual Age : 12 or 13
Clan                : Volturi Clan - Guard
Created By     :  Aro
Height             : 5"0
Hair Color       : Dark Brown
Eye Color        : Crimson Red
Skin Color       : Pale

Alec is a Vampire and a member of Volturi guard, serving as one of the highest ranked guards. He has a twin sister named Jane, who's also a high ranking member of the Guard.
Jane and Alec are the Volturi's most offensive weapons, as they both hold Abilities to completely take down an opponent, regardless of size. Alec possesses the gift of sensory deprivation. He can completely cut off all senses of multiple targets.
While Jane is useful in making an audience fear the Volturi, Alec is their most offensive weapon. 

Early Life
Alec was born in England around 800 A.D, son of an Anglo-Saxon woman and a Frankish soldier. He was born a few minutes after his fraternal twin sister, Jane. Both Alec and Jane had strong psychic abilities that were evident even in their human state.
Aro had shown interest in Alec and his twin sister Jane since they were toddlers, but decided to wait until they were old enough to turn them (the Volturi had already instated its rules about immortal children) so left them in the care of their parents. Their talents had not taken a focused shape at that point, but bad things happened to people who were unkind to the twins or their family, and good luck followed those who were friendly to them. Eventually, the superstitious locals found the twins too frightening to endure. They were accused as witches and condemned to be burned at the stake.
Aro was apprised of the situation by a nomad who knew of Aro's interest in the twins. Aro hurried to the village, arriving just in time to interrupt the execution. Transformed at the age of about 12 or 13, they are the smallest and youngest in appearance, as well as the most prized members of the guard due to their incredibly powerful gifts. It is said that they are the cornerstone of the Volturi's offensive abilities.
Though not directly said, they could be considered two of the most powerful vampires in the world gift-wise, capable of taking down opponents regardless of size or age.