His only canon appearance is in the final battle against Sagat in Street Fighter. This doesn't appear in the game, only in subsequent storylines.
He is called Satsui no Hado ni Mezameta Ryu in japanese, which means Ryu awoken by the surge of murderous intent. He became known as Evil Ryu in translations, but Capcom of Japan has stated that the correct name should be Dark Ryu. In Dark Ryu mode he destroyed a lot of stuff he took out most of japan with his Shinku Hadoken blast but he snapped out of it and returned to his normal state.
Ryu made his debut in the first Street Fighter as the primary playable character in the game, with his best friend, rival, and sparring partner Ken Masters serving as the second player's character. Both compete in the tournament depicted in the game in order to test their strength against the tournament's champion, Sagat.
His next appearance was in 1991's Street Fighter II. Set several years after Ryu defeated Sagat in the first tournament, Ryu participates in a second tournament. In his ending in the game, Ryu wins the tournament, but does not stay for the ceremony, already seeking his next challenge.
Ryu's backstory, along with those of other Street Fighter characters, would be explored in the subsequent Street Fighter Alpha prequel series. The first game, Street Fighter Alpha: Warriors' Dreams (1995), features Ryu confronting Sagat as his last opponent in a rematch following their first fight.Street Fighter Alpha 2 (1996) depicts Ryu on a quest to confront Akuma, his master's brother and enemy. After their match, Akuma reveals that Ryu possesses the "Evil Intent" (殺意の波動, Satsui no Hadō?, lit. "Surge of Murderous Intent", sometimes translated as the "Dark Hadou") within him, the same power Akuma uses. In the Street Fighter Alpha series, there is an alternative selectable version of Ryu known as "Evil Ryu". Similarly to Akuma, Ryu takes this form when succumbing to the evil intent, and becomes more violent. It was not until the international versions of the game, Street Fighter Alpha 2, that Evil Ryu was introduced as a secret character in the games. Evil Ryu was originally introduced in a 1996 Street Fighter Zero manga series authored by Masahiko Nakahira and later adapted in the Street Fighter canon by Capcom. In Street Fighter Alpha 3 (1998), Ryu is sought by M. Bison, who seeks to use him as his next host body.
Ryu and Ken would return in Street Fighter III (1997) and its updates. While Ryu's motivation in the game and rivalry with Ken would remain the same, he was also shown getting acquainted with several of the new characters featured in the game. Ryu appears in Street Fighter IV, which takes place after Street Fighter II but before Street Fighter III. A new appearance of Evil Ryu in a Street Fighter game was confirmed in Super Street Fighter IV: Arcade Edition by a teaser trailer, and later confirmed as a secret boss and playable character by leaked video footage.
Ryu has appeared in spin-offs related to the main Street Fighter series such as the Street Fighter EX series produced by Arika.Byron Mann portrays the character in separately produced arcade and console games based on the American film of the series, both titled Street Fighter: The Movie, where he wears Ryu's characteristic white karate gi and red headband.
Video game appearances
Street Fighter Alpha 2 (first appearance)
Street Fighter Alpha 2 Gold
Street Fighter Alpha 3
Street Fighter Alpha 3 Upper
Street Fighter Alpha 3 Max
Street Fighter Alpha Anthology
Street Fighter EX
Street Fighter EX Alpha
Capcom vs SNK
Capcom vs SNK Pro
Capcom vs SNK 2
SNK vs Capcom: Match of the Millennium
Super Street Fighter IV: Arcade Edition