"Zack Fair (ザックス・フェア, Zakkusu Fea) is a non-player character in the role-playing game Final Fantasy VII and the main protagonist of its prequel Crisis Core: Final Fantasy VII. Zack also appears in all the other titles in the Compilation of Final Fantasy VII. He originally was a minor character within Final Fantasy VII, but was given a basic backstory by a scenario writer. Zack was designed by Tetsuya Nomura and his name derived from 'fair weather', to contrast with Cloud Strife. Zack is voiced by Kenichi Suzumura in Japanese and Rick Gomez in English. Suzumura was chosen specifically for his voice by Nomura, and was given the role without an audition. Western critics have praised Zack's character, as well as his role within Crisis Core.
Although Zack's character is already dead by the start of Final Fantasy VII, he is mentioned when his best friend Cloud develops a mixed persona of his original self and Zack which is present until Cloud is able to recollect his past and regain his personality. Zack was also the first love of Aerith, a playable character from Final Fantasy VII. Throughout the game and other titles it is explained that when he was young, Zack joined the Shinra Electric Power Company's armed militia SOLDIER with hopes of becoming a hero. He was present when his friend Sephiroth went insane and destroyed Nibelheim, and attempted to stop him. However, he was defeated and later experimented on by Hojo before being killed by Shinra's military."
Source: Wikipedia, "Zack_Fair", available under the CC-BY-SA License.