In Street Fighter: Assassin's Fist, we learn in a flashback that Ryu was brought to Gouken's dojo by a mysterious old man.
I'm assuming he's supernatural in some way as he appears directly in front of Gouken, Gouken then looks away and looks back and the old man has suddenly moved maybe 30ft and is walking away into the distance.
Who is he?
Is this a character developed just for the movie, or is he someone is from Street Fighter lore?
I got my hands on a copy of the 143min uncut version and his identity is never revealed.
btw, it's a briliant movie, you should see it if you can
As Iankill suggested in the comments, he could be a reference to Shen Long, who was actually never a real character, more of an April Fool's joke / urban legend resulting from a mistranslation of something Ryu says in game.