Notes

Ryu is orphaned from such a young age that he has no memories of his parents. Then Gouken takes him in as a disciple and adoptive son. Gouken's best friend, a rich man from America, wished to discipline his spoiled young son and sent him to train under Gouken. The boy's name was Ken Masters. Ryu and Ken did not like each other initially, but Ken matured over time and they bonded over their frequent sparring matches. They would come to be best friends.
By the time Ryu and Ken were 23, Gouken deemed them good enough to try their martial art skills against the best fighters in the world. Ken would return to America, where he met his future wife, while Ryu would go to Thailand. At the time, Muay Thai was considered the most powerful martial art, and the best Muay Thai fighter, and by extension the best fighter in the world, was Sagat. Ryu knew that he couldn't just fight Sagat, Ryu hardly had a name for himself. Ryu set out fighting many Muay Thai fighters taunting them and belittling their sport. Soon, Sagat hears of Ryu and challenges him to a fight to protect the honor of Muay Thai. Sagat defeats Ryu in their fight and, when helping him up, Ryu is consumed by rage and lets out a near fatal Shoryuken which embeds a massive scar across Sagat's chest.
Soon afterwards, Ryu travels around and meets Akuma on an island. They fight, and Akuma loses. However, it is revealed that Akuma was simply testing Ryu and discovered that Ryu had a dark energy in him, the Satsui no Hado. Akuma smashes the island with his fist, leaving Ryu stranded.
Somehow, Ryu escapes from the island and meets up with Ken. They have a quick fight, which Ken wins, and Ken notices that Ryu is troubled. Ken gives Ryu his red hairband, Ryu had a white hairband in Street Fighter 1 and Alpha, and reminds him to remember his fight with Ken whenever he feels lost. To use it as guidance. Shortly afterwards, a fangirl of his, Sakura, asks to train under him. He rejects the offer, saying he is still on his own learning journey, but allows her to take a photo with him. After that, Sagat challenges Ryu to a fight. Ryu pleads Sagat to cancel the fight, for Sagat was still in pain from their last fight, but Sagat insisted. So they fought, but Ryu held back, allowing Sagat to win. Sagat would not realize this until much later on reflection.
Later, we know he, at one point, is confronted by Rose. She tells him that he does not have the power to defeat M. Bison without losing his soul. Ryu and M. Bison have a fight where M. Bison defeats Ryu. From there, M. Bison brainwashes Ryu seeking the Satsui no Hado within him on the realization that it is similar to his own psycho power. During this process, Ken, Sagat, and Sakura all arrive at the scene. Ken and Sakura fight off M. Bison while Sagat fights and tries to reason with the brainwashed Ryu. Soon, Sagat gets Ryu to his senses and the four of them (Ken, Sagat, Sakura, and Ryu) would temporarily destroy M. Bison.
After this we know that Ryu entered the World Warrior tournament. Additionally, we know that Ryu invited Ken to the tournament too. Besides that, we know essentially nothing concrete about what happened in the tournament. It's hinted that Ken and Ryu meet in bracket, and that Ken wins, and that Ryu probably made it to finals.
After the World Warrior tournament, Ryu is training in the desert where Akuma urged him to train with Satsui no Hado or else he would kill him. Ryu goes to a bar where he hears of an American champion who abandoned his family.
Ryu, who for obvious reasons believes it's Ken, goes to the address of this champion, but is ambushed by C. Viper. Cammy, to protect Ryu, ambushes C. Viper. Cammy, who is no match for C. Viper gets tortured by her. Ryu unleashes the power of Satsui no Hado on C. Viper, who somehow gets lucky and escapes with her life. In this rampage, Ryu, filled with rage, kills several S.I.N, the R&D sector of Shadaloo (M. Bison's evil organization), agents who had witnessed his fight against C. Viper. Chun Li, Ken, Guile, and Sakura comes to the scene to stop Ryu. Ken gets Cammy to the hospital and Sakura fends off against the possessed Ryu.
After a time, Ryu comes back to consciousness. He visits Ken's mansion and hears that Seth, the leader of S.I.N. wishes to capture Ryu for his connection to the Satsui No Hado. Because of this, Ryu tags along with Guile to infiltrate Seth's where Ryu fights Seth himself. Seth is a far superior fighter to Ryu and is destroying him in their match while giving Ryu a speech about his views on power. Ryu agrees that he does not know what true power is himself, but tells Seth that the one that Seth describes surely musn't be it. Seth continues to beat up Ryu, before Ryu unleashes a Hadoken infused the the power of nothingness (a power that grants invincibility and near-god-like-strength which is attained when the user clears their mind of all emotion and thought and focuses the power of nothing into attack) on Seth which kills him.