Movie
Description
Rin Matsuoka began his journey at Iwatobi Elementary School, transferring in and joining the swimming club where he forged friendships with Haruka Nanase, Makoto Tachibana, and Nagisa Hazuki. He deeply admired his late father, Toraichi Matsuoka, a fisherman who aspired to be an Olympic swimmer before dying in a sea accident. Rin adopted his father's Olympic dream as a way to remember him, inheriting his habit of snapping goggle straps before races and possessing distinctive shark-like teeth.

Following a relay tournament victory with his friends, Rin left Japan to study swimming in Australia before middle school. His time abroad proved challenging, fostering loneliness and self-doubt that altered his personality. Supported by homestay parents Russell and Lori, who gifted him a dog named Winnie, Rin persevered with swimming but grew distant from his friends in Japan.

Rin returned to Japan as a high school student attending Samezuka Academy. Initially cold and aloof, he joined the Samezuka swim team, intensely focused on defeating his perceived primary rival, Haruka. This obsession strained his relationships, stemming from unresolved guilt and pressure to fulfill his father's dream. His abrasive demeanor masked deep insecurities, leading him to isolate himself despite observing the camaraderie of the Iwatobi Swim Club.

A pivotal relay race, where Rin replaced Rei Ryugazaki, resulted in victory and restored his friendship with Haruka and the others. Confronting Haruka at their childhood meeting spot afterwards helped Rin realize his true desire was to swim with friends, not alone. He acknowledged that his father's dream had become genuinely his own, freeing him from its burden.

Maturing, Rin was appointed captain of the Samezuka swim team by Seijuro Mikoshiba. He learned to prioritize teamwork and mentorship, notably supporting teammate Aiichiro Nitori despite sometimes finding him overbearing. A trip to Australia with Haruka furthered his reconciliation with the past; Rin apologized for his earlier behavior and expressed admiration for Haruka's talent, openly sharing his struggles and demonstrating growth.

After high school, Rin returned to Australia for professional training under coach Mikhail Makarovich Nitori. Balancing training with international competition, he qualified for events like the All-Japan Invitational by winning the 100-meter butterfly. He maintained his rivalry with Haruka, now evolved into a mutual drive to compete together at the world level. Rin also reconnected strongly with childhood friend Sosuke Yamazaki.

Physically, Rin is muscular with maroon hair, red eyes, and sharp teeth. His height grew from 145 cm in elementary school to 179 cm in university, and his weight increased from 39 kg to 68 kg. His specialty strokes are butterfly and freestyle. He is protective of his younger sister, Gou Matsuoka, often interfering in her romantic interests. Personality-wise, he is competitive, passionate, disciplined, yet struggles with vulnerability. He enjoys meat, spicy foods, and survival games, dislikes sweets (though he consumes ice cream and cola), and keeps a tidy environment. He is an Aquarius, born on February 2.

Rin's key relationships include a deep, evolving rivalry with Haruka, a mentor dynamic with Aiichiro, a longstanding friendship with Sosuke, and a protective bond with Gou. His development concludes with him independently pursuing Olympic ambitions alongside Haruka, symbolizing his full acceptance of swimming for himself.