V.V.

V.V. (ヴイツー, Vuitsū), pronounced V2, was an immortal boy with blond hair longer than his body. He was the older twin brother of Charles zi Britannia, but looked much younger as a result of the power of immortality formed through a Geass contract. He could grant Geass contracts like C.C., having given both his brother and Rolo Lamperouge their Geass abilities, among others in the Geass Order such as Orpheus Zevon, Euliya, and Clara Lamperouge. He succeeded C.C. in becoming leader of the Geass Directorate, a secret organization that researches and creates Geass users. He is one of the main antagonists in the series.

Character Outline
He is the older twin brother of Charles zi Britannia, but as he has become immortal at the early age of 10, there is a seemingly immense age difference between them (his exact age is unknown, though being twins, he is most likely the exact same age as his brother, 63). C.C. refers to V.V. as Charles' first ally and has indeed been actively supporting him in his childhood years. Charles and V.V.'s childhood years were marred by an internal feud in the Imperial Family called the Emblem of Blood. This period filled with deception and assassination resulting in the deaths of various members of the royal court including their mother. This event convinced the two to create a Geass contract to create a world without lies and to do so, they intended to destroy the "Gods". Several years later, Marianne Vi Britannia and C.C. joined in their venture as well.

First Season
During the time of both the invasion and Black Rebellion, V.V remained behind the scenes hiding among the highest ranks of the Britannian Royal Family. He and Charles were starting expeditions to find Thought Elevators across the planet. He was seen briefly transporting Lelouch, Suzaku, Kallen, and Euphemia to Kamine Island in episode 18. He apparently knew of Lelouch's actions, particularly his use of Geass. V.V. appeared again to Suzaku Kururugi to tell him about Geass and that Zero was responsible for Euphemia Li Britannia's sudden change. After that, he kidnapped Nunnally Vi Britannia and once again disappeared into the Sword of Akasha using a Thought Elevator, resulting in Lelouch's sudden abandonment of the Black Knights' chain of command.

Second Season
V.V was more active during the Black Knights' second uprising. He leads the Geass Directorate, a secret organization that studies and produces Geass users, as with Jeremiah Gottwald's Geass Canceler.

When Cornelia comes to stop the Geass research, she tries to kill V.V by throwing a knife at him (assuming him to be an individual with a Geass power). He shocks her by pulling the knife out, despite that it was buried deep in his forehead and tells her that, as her uncle, he is proud of her skills and takes her prisoner. The research had stopped as the Black Knights invaded the Order killing all the researchers, civilians, and subjects, as well as eliminating all traces of their research.

In the ensuing chaos, he pilots the Siegfried during Lelouch's assault on the Geass Directorate. When Jeremiah, the original pilot of the Siegfried, expressed outrage at this, V.V. called him out for his treason, as well as expressing rage when Jeremiah mentioned Marianne. Though he manages to hold his own at first, he is caught off-guard by Cornelia, who has hot-wired a damaged Akatsuki with an array of weapons. She and Lelouch destroy the Siegfried together. He manages to reach the Twilight Door to the Thought Elevator in the complex only to have his Code taken by Charles, causing him to succumb to his wounds and granting the Emperor immortality.

In a flashback, it is revealed that V.V. was the one who assassinated Marianne, having done so out of jealousy. He lies about this to Charles, breaking his promise of mutual honesty between him and Charles.

Code of Immortality
V.V. is ageless and immortal as a result of his code of immortality. He can also grant Geass contracts like C.C., having given both his brother and Rolo Lamperouge their Geass abilities, among others in the Geass Order.

Knightmare Skills
V.V. is an accomplished Knightmare pilot. The only Knightmare that was known to be piloted by him was the Siegfried during the Assault on the Geass Order.

Code Geass: The Manga
In the manga adaption of the series, V.V. is presented with some similarities and some differences to his anime counterpart. During the Geass cult raid, instead of Charles, he intended to obtain C.C's code which she planned to surrender only to be pushed away as Lelouch damages the Sword of Akasha. Afterwards he dies the same way he does in the anime, Charles stealing his code.

Code Geass: Oz The Reflection
V.V. takes up the antagonistic role of Code Geass Oz The Reflection as he is the one who produced other Geass users. At some point, he also takes control of Pluton.

Trivia

 * V.V., despite being of the same age as Charles, seems to still retain the mentality and mannerisms of a 10-year-old boy, often saying "Oh yeah?" in a taunting, childish manner.
 * According to audio commentary, V.V.'s Code appeared on the back on his neck.
 * V.V. and Empress Tianzi are the only characters that are voiced by child actors.
 * In Super Robot Wars Z2, 4 years later and his voice has already transformed and voice acting is significantly different from Anime.