William Dunbar

""You're nothing. Just an insignificant bunch of digital dust.""

- William while possessed by X.A.N.A.

William Dunbar is a major antagonist in Code Lyoko. He is one of the students at Kadic and Yumi's crush, as well as Ulrich's rival. He is also the only character aside from the main group to ever enter Lyoko, but it only caused him to be brainwashed and captured by X.A.N.A., who turned William into his general for most of the series until the series finale. He was voiced by David Gasman, who also voiced X.A.N.A.

Role in the series
William entered as a new student in the second season and immediately began to develop a crush on Yumi, causing jealousy on Ulrich, who also liked her. The group didn't have much to worry about him until the day he discovered Lyoko and X.A.N.A., offering his help in stopping the supercomputer. Jeremy was reluctant at first, but decided to create a form for William on Lyoko. However, the moment he entered, X.A.N.A. took control of him and destroyed an entire area of Lyoko, also absorving William onto his data and putting him against the group. Jeremy devised a clone to replace William while he was still under X.A.N.A.'s control, while the group rebuild Lyoko little by little. Near the series finale, they manage to take William out of Lyoko and cut X.A.N.A.'s control over him. However, X.A.N.A.'s final attack began once he possessed William once again, but they managed to finally kill the computer and save William, Ulrich finally getting on good terms with him.

Personality
William, at first, is a normal teenager with average good looks and attractiveness. However, he can be very tactical and smart when he wants to, making it easy for a girl to fall in love with him. He also can be friendly and protective of someone he cares about, like his closest friends or crushes. This all changes, however, when he is controlled by X.A.N.A. in the end of season three. William becomes greedy and cold, completely absent of emotions aside from malice and hate, and his voice goes from a calm and conforting tone to a harsh, computer-altered commanding voice.