Street Fighter Alpha: The Animation

After leaving the building, Ryu finds Shun among other sampled children, where after calling his name, he begins crying out apologies to Professor Sadler and sobbing on the grass, leaving Ryu just a bit pissed off. Sadler can sense his torment, and notes that with that pain, the Dark Hadou will grow gradually, and all this energy is being absorbed into him. The two fighters rescue Birdie, and sense another person in the hall with them. Chun-Li believes it is Ryu, but Ken corrects her. "That chi is not Ryu's. This chi is pure evil."
 

It turns out to be that warrior Ryu fought at the Kabuki Town tournament, and proceeds to kick the shit out of them. Chun-Li is ordered to take Birdie to safety while Ken fights the warrior, even though every attack from the three of them has proved useless. The warrior powers up, using a familiar chi to his advantage.
 

Meanwhile, Ryu is then attacked by three bizarre characters, although they're quickly taken care of. The chi is familiar to him as well, and begins taking him over. The warrior fires a laser, wrecking part of the building, and proceeds to pick on a weakened Birdie, slamming him and choking him until Chun-Li stops him, only to be his new punch puppet. Ken struggles in as Chun-Li escapes his grip, and warns him that this warrior isn't fighting for the same thing they are, and falls unconscious. Ken, however, is a trooper and continues fighting, even when a face grows out of the warrior's chest and he fires a laser that kind of completely destroys the building.

Ryu finally turns his attention to the destruction going on there, and begins fighting the warrior, only to hear Shun's voice. The face that came out of his face is that of Shun's, and after telling a mood-ruining joke, begins insulting him for falling into such an obvious trap and claims that he isn't actually his brother in an attempt to build up his Dark Hadou. He warns if he doesn't use the Dark Hadou against him, Ken will be killed.
 

That matter is dropped in only a few seconds after Shun sees that Ryu is finally angry, and lets him offer a few Hurricane Kicks, aerial punches and Hadokens to the face, thus providing Sadler with more power. However, none of them used the Dark Hadou, so Shun just flat out says it that the warrior has incorporated data from all the other fighters, and the only way to be killed is with a Dark Hadou.

To provoke a bit more hate, the warrior knocks Ken about for a moment, and looks like he's about to finish him off until Chun-Li intercepts, only to be the new target. Ryu is trying to suppress his rage, but Ken makes it public, and uses a charged-up Shoryuken on the warrior, which merely displaces his jaw. Ryu then charges his much more powerful Dark Hadou, and fires it off, despite Ken's wishes for him not to.

The shot blasts Shun straight out of the warrior's body, utterly demolishing it and making Sadler ecstatic. With his fully powered body, he leaps out of his machine and into the ring, and beats Ryu senseless, and plans to "swallow [him] up with [his] evil." That's what he actually says. He then, however, suggests that perhaps he will be swallowed up by Ryu's evil.

The two of them begin charging Dark Hadou fuelled Hadokens, but Ryu is then seen by Rose, who reminds him that he has not turned over the Card of Death yet. Shun urges him not to fire, Ken reminds him that he will never be the same as Akuma, Chun-Li gives support while showing off her ass, while Sakura finally realises that Ryu keeps fighting to find the answer.

Back to the Hadoken charging! Sadler fires his, which engulfs Ryu, but actually double charges his Hadoken, and its blast leaves Sadler utterly decimated, who crumbles into nothingness.
 

He heads on over to Shun, who tells him that he always wanted to see him fight, and asks him why he came. Ryu reminisces on the times they had together, the bonding they had, while Shun questions why he came, even though it was clearly a trap, and he never believed he was his brother. Ryu, smiling, tells him that he is his brother.
 

Shun admits that he fought for money, and hoped that with it, he could have helped his mother. He questions his actions, and says goodbye to his brother, before passing away.

Epilogue

Chun-Li has returned to working for Interpol, being her usual punk pounding self.

Sakura still fights in hopes of being able to duel Ryu when she sees him.

Ken returns to tournament fighting, and remains the champion of the American tourneys.

Ryu continues his training, and duels with Akuma to overcome the struggles inside him, aiming to avoid following his same path.

The three guys Ryu fights are promptly defeated and never talked about again, making me wonder why they were even included.

When everyone is talking about Ryu using the Dark Hadou on whoever he's fighting, they keep referring to it as "shoot[ing] off a Dark Hadou," which just sounds a bit stupid to me.

After the fight in the hallway, Birdie isn't seen again, and you don't actually see the fighters from earlier escape.