Zero is a character from the Mega Man X series of games, as well as the main protagonist of the Mega Man Zero series. He was the last robot that Dr. Wily created, which he considered his greatest. However, due to a flaw in his programming, Wily put Zero away in a capsule, only to be awakened decades later prior to the first Mega Man X game.
When first awokened, Zero was a Maverick, but was defeated by Sigma. Afterwards, he became a Maverick Hunter, eventually partnering with Axl and Mega Man X. He is somewhat cold and distant towards others, and he doesn't consider himself a hero. Zero appeared in every Mega Man X game, as well as every Mega Man Zero game. He makes an appearance as Biometal Z in the Mega Man ZX series, as well as being a playable character in SVC Chaos: SNK vs. Capcom, Onimusha: Blade Warriors, Tatsunoko vs. Capcom: Ultimate All-Stars and Marvel vs. Capcom 3: Fate of Two Worlds. He is also set to appear in the upcoming crossover RPG, Project X Zone, where he is part of a Pair Unit with Mega Man X.