Ryō Mashiba's journey through the ranks of professional boxing is punctuated by a series of unforgettable, often brutal, encounters that have defined his career and character. Mashiba first made his name in the East Japan Rookie King Tournament, tearing through his competition with ruthless efficiency. Each match was a showcase of his deadly precision and his willingness to inflict pain. His semi-final match against Ichiro Miyata, a counterpunching genius, was particularly controversial. Facing a disadvantage as Miyata nullified his flicker jabs, Mashiba resorted to stepping on Miyata's foot to maintain his proximity and gain an edge, a move that cemented his reputation as a fighter willing to do whatever it took to win. This controversial victory propelled Mashiba into the high-stakes final against the series' protagonist, Ippo Makunouchi. This fight was a clash of titans, with Ippo's unrelenting aggression and unmatched durability meeting Mashiba's predatory precision. As the battle raged, Mashiba found himself pushed beyond his limits, a rare occurrence for him. Ippo's relentless pressure battered through his defenses, forcing Mashiba into a deep-water, all-out battle of attrition. Despite his formidable flicker jabs and chopping right, Mashiba ultimately fell to Ippo's tenacity and the destructive power of his Dempsey Roll. This loss, Mashiba's first significant defeat, was a turning point, igniting a thirst for redemption and prompting his move to a higher weight class. Following his devastating loss to Ippo, Mashiba refused to let defeat define him. With unwavering resolve and a thirst for redemption, he moved up to the Junior Lightweight Division, determined to carve a new name for himself. His flicker jabs became even sharper, his chopping right more merciless, and his determination reached a new level. Each fight in this new division was a brutal statement, a stark reminder to the boxing world that Mashiba was a rising force to be reckoned with. His relentless pursuit paid off when he was crowned the Japanese Junior Lightweight Champion. One of his most intriguing title defenses was against Tatsuya Kimura, one of Ippo's stablemates and a close friend. Unlike many of Mashiba's previous elite opponents, Kimura was an underdog, but one who had trained relentlessly, developing a unique "Dragon Fish Blow" specifically to counter Mashiba's flicker jabs. This fight showcased Mashiba's champion-level resilience and adaptability, as he weathered Kimura's surprising composure and specialized attacks, eventually defending his belt in a very close match. The fight was a testament to both Mashiba's continued dominance and Kimura's incredible heart. The bout against Ryūhei Sawamura, the "Owari Dragon," is perhaps the most infamous and brutal fight in Mashiba's career, and arguably one of the dirtiest and bloodiest matches ever seen in Hajime no Ippo. This fight was fueled by intense personal animosity, as Sawamura had previously disrespected Kumi Mashiba. Ryō entered the ring with a burning grudge, explicitly stating his intent to "kill" Sawamura. What ensued was less a boxing match and more a street brawl disguised as a professional fight. Both fighters disregarded rules, resorting to illegal elbows, headbutts, and blatant fouls. Mashiba, usually a master of controlled aggression, descended into unbridled rage, determined to inflict maximum pain on Sawamura. The fight was a raw, visceral spectacle of mutual destruction. Despite landing devastating blows and pushing Sawamura to his limits, Mashiba ultimately lost by disqualification due to his brutal and uncontrolled actions. This fight, while a defeat, underscored the depth of Mashiba's protective instincts for Kumi and the dark side of his fighting spirit when provoked. It was a raw display of a character pushed past the point of no return, where victory became secondary to vengeance. After the tumultuous encounter with Sawamura, Mashiba once again demonstrated his incredible resilience and unquenchable thirst for redemption. He continued his ascent, eventually claiming the Oriental Pacific Boxing Federation (OPBF) Lightweight title, solidifying his dominance and securing a coveted world ranking. This victory positioned him as a legitimate contender for a world title, a dream that had been brewing since his debut. His opportunity came against the highly skilled and flamboyant WBC Lightweight World Champion, Marcus Rosario. This fight represented Mashiba's ultimate test, pitting his unique style against a technical mastermind who blended speed, power, defensive prowess, and "world-class shenanigans." Mashiba struggled through the early rounds, with Rosario expertly slipping past his flicker jabs and counter-punching with pinpoint accuracy. However, Mashiba's legendary endurance and adaptability allowed him to slowly break through Rosario's defenses. As the fight neared its climax, Mashiba delivered a devastating "Chopping Right" that seemed to have secured him a victory, solidifying his legitimacy beyond Japan. Yet, in a cruel twist of fate that highlighted the unforgiving nature of boxing and perhaps the lingering consequences of his brutal fighting style, Mashiba collapsed at the very edge of victory. A stumble, their feet entangled, and Mashiba fell hard, injuring his spine. Just as he was about to land the final blow, his body gave out, he fainted, and he couldn't finish the fight. He lost the match, a heartbreaking end to what could have been his crowning achievement. This recent development, as of early 2025 in the context of the series, has left his career and condition uncertain, raising questions about his future in the sport.