Vincent Valentine
In the backstory to ''Final Fantasy VII'', Vincent is a Turk assigned to guard the scientist Lucrecia Crescent, whom he falls in love with. After a series of scientific experiments involving the cells of the extraterrestrial lifeform Jenova, Crescent gives birth to the game's antagonist, Sephiroth, with Professor Hojo being the father. Soon after, Vincent became a test subject to experiments performed by Hojo after he shot him. This resulted in genetic modification that supplanted other forms within him and gave him superior strength, speed, and healing in addition to not aging. If the player unlocks Vincent, he will join Cloud Strife's group to stop Sephiroth and seek revenge on Hojo.
Due to time constraints, Vincent was originally not intended to be playable in ''Final Fantasy VII'', but was ultimately made an optional character. Despite his optional status and lack of concrete detail regarding his background, he proved to be popular with both fans and critics, and his history was expanded upon in other installments of the ''Compilation'', primarily ''Final Fantasy VII: Advent Children'' and ''Dirge of Cerberus''. Provided by Wikipedia