Vincent was once a member of the Shin-Ra Company's Turks, a group of highly skilled operatives who specialized in various activies such as espionage, kidnapping, assassinations and serving as bodyguards. When he was assigned to supervise a project spear-headed by his father Grimoire, he fell in love with a scientist named "Lucrecia Crescent," an assistant to his father. However, despite his feelings for her, they parted ways when Grimoire died saving Lucrecia's life. Vincent would later meet her for a second time while assigned to supervise the Jenova Project in Nibelheim, where she was serving as an assistant to Professor Gast. There, Vincent tried expressing his feelings to her, but she rejected him out of guilt over Grimoire's death, ultimately entering a relationship with her associate Hojo instead. Lucrecia became pregnant afterwards, supplying a test subject for the Jenova Project's intentions to investigate the effect of Jenova cells on an unborn child.



Vincent objected to the use of humansespecially Lucrecia and her unborn child, whose parentage he was uncertain ofas live test subjects. Even so, in the interest of science, Lucrecia proceeded with the treatment and suffered various ill effects as a result. Outraged, Vincent confronted Hojo in the Shinra Mansion's underground laboratory and a heated argument ensued. Hojo ended this confrontation by pulling a gun from his lab coat and shooting Vincent down in cold blood. Vincent's body was placed in a large experimental capsule for use in Hojo's experiments based on Lucrecia's research of the Lifestream, originating from the time of her assistance to Grimoire. While Hojo's experimentation resulted in Galian Beast, Hellmasker, and Death Gigas (creatures he can transform into) becoming part of Vincent's anatomy, Lucrecia exposed Vincent's body to G Substance, a contaminated form of mako, and he became Chaos, an entity intended to pave the way for Omega WEAPON by killing all living things.



Under the influence of Chaos, Vincent became consumed in feral rage and broke out of his confinement. Lucrecia then used a materia that could control Chaos' power to calm Vincent and place him in a deep slumber. By the time Vincent reawakened on the operating tablewith Hojo and Lucrecia nowhere in sighthe responded to his modified body with both anguish and rage. Later, during the time frame of the game, Vincent is discovered by Cloud's party in a locked room in the basement of the mansion. Here, he had been slumbering inside a coffin for some 23 years as a self-inflicted punishment for his inability to prevent the Jenova Project, which Vincent referred to as his "sin." He then joins AVALANCHE in their quest to stop Sephiroth.