Sosuke Yamazaki is a main character from the anime series Free!. He is a talented swimmer specializing in the butterfly stroke and is known for his stoic and serious demeanor. Sosuke is a childhood friend of Rin Matsuoka and transfers to Samezuka Academy to swim alongside him. Throughout the series, Sosuke struggles with a shoulder injury that threatens his swimming career, adding depth to his character as he navigates the challenges of friendship and competition. His dedication and loyalty make him a respected and formidable competitor.