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Street Fighter Alpha (known as Street Fighter Zero in Japan) is a manga adaptation of the game series of the same name, written by Masahiko Nakahira. It has two volumes, and was the franchise's debut of Evil Ryu.
The book starts off at Southeast Asia, off the coast of Thailand, right after the first Street Fighter tournament. Ryu, who is in doubt about his future as a warrior has hitched a ride with Birdie and two thugs off their heroin drug boat. Birdie gives Ryu words of encouragement by telling him that his true passion is fighting, and that his experience with him had earned his respect, prompting him to become more than just a street thug. While sailing, they are intercepted by Interpol who sends Chun-Li to arrest them. The female officer takes out one of the thugs and faces Birdie, who holds his own against her. However, as they’re fighting, an Interpol sniper takes a shot at Birdie, but Ryu leaps in the way and takes the bullet for him.
In critical condition, Ryu begins to bleed out as Chun-Li calls in medics to help him. However, Ryu inadvertently taps into the powers of the Dark Hado and shoots out the sniper bullets from his chest and immediately heals up. He urges the others to run as they’re baffled by his power. As he loses himself to his power, Ryu remembers his master Gouken’s teachings of their fighting style, how their master Goutetsu evolved their fighting style to a true martial art and warning them of the Dark Hado and of its murderous intent. Ryu ultimately succumbs to its power and uses his Tatsumaki Senpukyaku attack to leap over to an Interpol ship and attack the officers within. They fight back, but Evil Ryu easily evades their attacks and begin destroying the ship. Chun-Li and Birdie engage in a temporary truce to stop Evil Ryu before he causes further damage.
As they arrive on the Interpol ship, Evil Ryu senses their presence and fires several Hadoken projectiles through the floor, narrowly missing Chun-Li and Birdie. As Chun-Li counters with her inferior Kikoken attacks, Evil Ryu rips through the ship and attacks them. Birdie and Chun-Li are no match for Evil Ryu, but the street thug manages to grab hold of him, prompting Chun-Li to attack them both. Chun-Li unleashes her Kikoshou attack at both (with Evil Ryu taking the blunt of the attack), hoping to end the fight in one blow. Unfortunately, the attack has little effect on Evil Ryu, forcing Chun-Li to fire more until he drops. Resisting her ultimate special, Evil Ryu attacks Birdie, releasing his grip on him and confronts Chun-Li as she runs out of ki. Down but not out, Birdie urges Evil Ryu to wake up just as he is about to kill her. Birdie’s words ultimately sink in as Ryu stops himself midstream of his Shoryuken attack and collapses onto the ground.
Ryu, Birdie and his thugs are taken to Interpol Headquarters in Paris where Ryu is questioned about his knowledge of the Dark Hado. He talks about his fight with Sagat during the first Street Fighter tournament, and how wasn’t strong enough to defeat the Muay Thai fighter on his own. He remembers revealing his Shoryuken attack to Gouken and Ken by obliterating a gigantic boulder, only to be displined by Gouken. He discusses the lack of proper training could make the wielder a slave to its power and that he should never use it. However just as he is beaten by Sagat, he taps into the Dark Hado and uses the Shoryuken to defeat the Muay Thai fighter, scarring him in the process. Believing he has thrown away his honor as a warrior, he joined Birdie as a bodyguard for drug deals. Chun-Li scolds Ryu, telling him that Sagat would be disappointed if he knew Ryu have gave up and quit, and should instead fight to conquer the Dark Hado and face Sagat once more. Her words renewed his confidence in himself, resuming his journey as a true warrior.
Interpol released Ryu on the condition that he helps them in their pursuit against the criminal organization, Shadaloo. They’re currently scouting fighters from all over the world, including Sagat. And since Ryu had recently defeated the Muay Thai fighter, Interpol believes he would be the top fighter that Shadaloo is scouting for. Chun-Li and Ryu arrive at a street fighting epicenter in Paris, where they believe Shadaloo will make contact with him. As they travel through the sewers with a guide to the epicenter, Ryu slips and falls into the murky waters, meeting with a fortune teller named Rose. She warns him of his future and berates him of his uncertainty of her powers. Ryu attacks Rose with a Hadoken, but she easily deflects it with her Soul Reflect, warning him about his future with the Dark Hado. She tells him to head south, where he’ll meet “two men in red who are like fire”, stating that those two will help him conquer the Dark Hado. Ryu rises from the waters, realizing that his experience with Rose was just a vision. Ryu, Chun-Li and their guide bump into the real Rose on their way to the epicenter, who shows no sign of recognizing Ryu from their “encounter”.
Ryu discusses his encounter with Rose to Chun-Li at fighting tournament in the Caribbean, telling her of the two “men in red” he should look for, believing one of them to be his friend, Ken Masters. They watch the match as Dan Hibiki faces off against Ken during the final match for B Block. Ken immediately notices Ryu and Chun-Li within the audience, mocking Dan by warning him of a quick and painless defeat. Ryu and Chun-Li study Ken’s moves, and just as he is about to defeat Dan, he ends the match with a Shoryureppa attack. Ryu is distraught that Ken used a variant of the attack forbidden by Gouken and confronts him about it after the match. Ryu urges Ken to spar with him, hoping that their fight will somehow help him conquer the Dark Hado.
Chun-Li tries to stop them, ignorantly believing that their fight will unleash the Dark Hado from both of them. Ken, who doesn’t believe in the Dark Hado, ignores Chun-Li’s pleas and begins the fight. They match each other blow for blow until Ken finds an opening and unleashes his Shoryuken on Ryu. Ken states that the Shoryuken, Tatsumaki Senpukyaku and Hadoken were part of their training to create balance, and that Ryu shouldn’t hold back because of mere superstition. Ken goads Ryu into using it, only to enrage him as he states his fear of the dangers the Dark Hado possess. Ken reveals that he can’t believe in it, because if he did then he would have to kill Ryu.
Ken reminisces a conversation he had with Gouken just days prior to his death. Gouken feared that Ryu is an individual that possesses the power of the Dark Hado, and that if he ever does awaken that power, that Ken himself should be the one that kills. He announces that their spar has now become a death match, and that Ryu shouldn’t hold back. Ken goads Ryu into attacking him with a Shoryuken, but doesn’t go through with it. The two proceed to go all out against each other, beating each other until neither could no longer stand. Ken states that the Shoryuken is nothing more than an attack that just needs to be mastered. Ryu agrees with Ken, stating that once he masters the Shoryuken, it’ll bring him one step closer to being a true warrior. Ken gives Ryu the headband from his ponytail and makes him promise that he’ll be the first opponent once Ryu masters the Shoryuken.
As Ryu and Ken crudely patch themselves up from their fight, they come in contact with Charlie Nash, who have been looking for Chun-Li and Ryu. As Ryu and Ken get proper medical attention, Charlie informs Chun-Li that the Caribbean matches were nothing more than a decoy by Shadaloo and that the real matches are somewhere in South America. Since the upper levels of the U.S. Army are under Shadaloo’s control, Charlie himself had to go undercover to stop the criminal organization. Ken informs Ryu about Guy, a vigilante who travels around the world beating up thugs and fighters. He reveals that he went to the Caribbean to fight him, believing that he couldn’t resist an underground tournament filled with crooks. Ryu deducts that the second “man in red” is Guy, and demands to join Charlie and Chun-Li to Guy’s location.
As they travel to South America, Ryu’s body has completely healed from his fight with Ken while he has still sustained crippling injuries, believing that the Dark Hado is responsible for Ryu’s accelerated healing. Chun-Li, Ryu and Ken make it to the vacation home of Vega, who is aware of their presence and allows them to proceed to the arena. Meanwhile, during the fighting tournament, Eagle loses his battle with Adon. He kills Eagle as he has done to several fighters prior, pleased that Ryu will be on his way to the fighting tournament.
Ryu, Ken and Chun-Li arrive at the underground fighting tournament, where Vega greets them as the host of the tournament. Being viewed from a monitor, Vega reveals the audience as hundreds of other monitors observing the fights, the viewers being weapon dealers and crime bosses from around the world. They observe a one-sided fight between Cammy and Dan Hibiki. Vega reveals that Cammy is the result of genetic manipulation thanks to Shadaloo and that she his superior to most fighters in every way despite her young age. Vega orders Cammy to slay Dan, but their fight is interrupted by Sodom. Vega reveals that in this unique arena, multiple fighters can join the battle at a time, however the ceiling drops like a compactor if more than one fighter are in the ring. Sodom throws the weakened Dan out of the arena and engages in battle with Cammy. He easily overpowers her and nearly knocks her out from the arena as well, crushing her hands with his foot, the injuries freeing her from Shadaloo’s control, as well as triggering her pain to Sodom’s attacks. As Ryu tries to help Cammy, Adon intervenes through one of the monitors. Vega reveals that Adon wanted revenge on Ryu for defeating Sagat and dishonoring the art of Muay Thai, and that Shadaloo was more than happy to fulfill his wish. Vega pushes Chun-Li’s buttons by goading her about her father and how he too had fought in the compactor arena. Chun-Li rushes to save Cammy from falling and once more triggers the ceiling into coming down on them.