Movie
Description
Renji Yanagi, a third-year at Rikkaidai Fuzoku Middle School, stands 181-182 cm tall and holds a key position on the tennis team as one of the formidable "Three Demons" with Yukimura Seiichi and Sanada Genichirou. Born June 4 (Gemini, blood type A), his family consists of grandparents, parents, an older sister, and a cat, with his father employed as an accountant.

Yanagi's tennis foundation began in childhood under Mitsuya Akuto, mastering data tennis through statistical analysis and psychological prediction. He later attended a tennis school where he partnered with Inui Sadaharu, dominating junior doubles. Their partnership ended abruptly when Yanagi moved to Kanagawa without informing Inui, leaving a childhood match unfinished at 5-4 in Yanagi's favor, creating a lasting rivalry unresolved until their Kantō Tournament finals reunion.

As first-years at Rikkaidai, Yanagi, Yukimura, and Sanada became regulars, leading the team to consecutive national championships. Yanagi serves as team treasurer and strategist, mentoring volatile second-year Kirihara Akaya. During the Kantō finals against Seigaku, Yanagi faced Inui in Singles 3, recreating their childhood match. Despite early dominance, Yanagi lost in a tiebreak, marking Rikkaidai's first finals loss. He accepted responsibility and requested Sanada's disciplinary slap, though Kirihara intervened.

In the National Tournament, Yanagi partnered with Kirihara in Doubles 2 against Inui and Kaidō. He permitted Kirihara's aggressive "Devil Mode" to continue even when Kirihara targeted Inui, resulting in Seigaku's forfeit after Inui's collapse; Yanagi later justified this as tactical pragmatism.

At the U-17 Camp, Yanagi initially forfeited a tiebreak match against Kirihara to foster his growth. During "Revolution" matches, he confronted mentor Mitsuya but lost motivation upon calculating a 0% win probability. Inui's intervention spurred him to momentarily discard data, though he still lost. Yanagi then passed his collected data to Inui, who defeated Mitsuya. Yanagi subsequently joined the Japanese representatives for the U-17 World Cup, winning a doubles match against France's Edgard and Jonathan.

In the "Hyotei vs Rikkai Game of Future" OVA set post-U-17 World Cup, Yanagi partnered with Sanada in Doubles 1 against Hyotei's Kabaji and Ootori during Rikkai's third-years' final interactions with underclassmen before graduation. They won 6-4, countering Kabaji's ability to replicate techniques.

Off-court, Yanagi is reserved, analytical, and observant, often speaking concisely. He mentors Kirihara and is considered the most approachable of Rikkai's "Big Three." His hobbies include reading pure literature (e.g., Izumi Kyōka), gagaku music, haiku, tea ceremonies, tending a kokedama plant, mental arithmetic, shogi, interpreting, and frequenting secondhand bookshops. His counter-punching playstyle features techniques like "Kamaitachi" (high-speed slice) and "Utsusemi" (non-bouncing slice).