Charlie

Charlie is first mentioned by name in the Street Fighter II storyline (first released in 1991), where he is the deceased war buddy of Guile, one of the playable characters in the game. Prior to the events of the game, Charlie was killed by M. Bison, although the exact circumstances are not clear (in the English localization of the game, it is said that he was taken captive during a mission and later died during the escape attempt). In the game, Guile enters the World Warrior tournament with the purpose of avenging his fallen friend’s death. In Super Street Fighter II Turbo, a scene is shown of Guile visiting Charlie’s grave.
Charlie would later be made into a playable character in Street Fighter Alpha, a prequel set before the Street Fighter II games. In the Alpha storyline, Charlie was the previous U.S. Martial Arts champion for two years (a record succeeded by Ken) and was also the one who taught Guile some of his fighting techniques (explaining their similar fighting styles). In the game, Charlie is given the duty to track down Bison and uncover corruption within the American military. In his ending, Charlie defeats Bison, but only to be struck from behind by him shortly afterwards.
Despite Charlie’s death in the first Alpha game, he would return as a playable character in the two succeeding Street Fighter Alpha games. Street Fighter Alpha 2 features a different depiction of his death during his ending – after defeating Bison, he is shot from the back by his intended backup helicopter and falls from the waterfall. In Street Fighter Alpha 3, he has an ending where he actually survives battle and manages to destroy Shadaloo’s secret base. In the console ports of Alpha 3, Guile is added to the playable roster as well. In Guile’s storyline, he is ordered by his superiors to track Charlie, who has supposedly gone AWOL. In reality, Charlie was undercover to investigate Shadaloo and its connection to the military, whereas Guile was sent to put a stop to him without knowing it. After realizing, Guile defeats Bison and teams up with Charlie to destroy Bison’s Psycho Drive. Guile escapes, while Charlie stays behind to hold off Bison and is presumed dead after the explosion.
Though Charlie is not a playable character in Street Fighter IV, Guile believes he is still alive because no one found his body. Before the rival fight between Guile and Abel, it is presumed that Abel may know information about Charlie after Guile demonstrated a Sonic Boom. Guile wanted answers, but none were given. It is hinted at, but never confirmed, that Abel’s adopted father, a retired soldier, may have been Charlie himself.
X-Men vs. Street Fighter features a different outcome for Charlie where he becomes Shadow (see below). Outside of fighting games, Charlie is a playable character in Cannon Spike.