Ryu's bio
The Games

Full Name: Ryu (no, Hoshi is not his last name.  Don't listen to Steven Desouza)
Birthday: July 21, 1964
Nationality: Japanese
Blood Type: O
Height: 175 cm
Weight: 68 kg
Likes: Mizuokan (Japanese Sweet Bean Jelly)
Dislikes: Spiders
Fighting Style: Shotokan/Ansatsukan karate
First Appearance: Street Fighter 1 (Player 1)
Unless you've been living under a rock or picked up a strange case of amnesia, you should really need no real explanation as to who Ryu is. Not only has Ryu been present in every Street Fighter created, but Ryu is also the main character of Street Fighter, and one of the main trademark characters of Capcom (the company that made Street Fighter) When people think of Street Fighter, they usually think of Ryu first (or Chun Li, but that's another story...)
Anyway, a lot on Ryu's past is still shrouded in mystery (which is ironic when Cammy is supposed to be the one with the mysterious past, but I digress).  Nothing is known of his parents, or even his last name (don't dare say Hoshi).  About the only thing known is that Ryu has been growing up in Gouken's Dojo ever since he was a kid. 
Ryu seemed to have quite a knack for the martial arts.  It was almost like he was born to do it.  Ryu was dedicated, calm, focused, serious, and quiet, all good qualities to have for the martial arts, but bad when it came to public situations.
Ryu fights basically for the thrill that he gets from facing strong opponents, and to find out if there is more to martial arts then just what everyone already sees.  He seeks the true meaning of the fight, and continues this quest in hopes of acheiving it.