Morisuke Yaku, a third-year Nekoma High libero, combines a compact 165 cm frame with sandy blond hair and sharp brown eyes. His athleticism defies his stature, boasting a 301 cm jump reach, while his libero uniform—a white jersey with red-black accents, red shorts, and knee pads—contrasts his post-timeskip preference for sharp suits. Commanding Nekoma’s defense with precision, Yaku’s fiery temper flares at height-related jabs, earning him the "demon senpai" moniker. His mentorship shines through clashes with tactless first-year Lev Haiba, balancing stern guidance with a Sugawara-like nurturing approach for proteges like Shibayama. A rivalry-turned-partnership with Kuroo, forged through middle school clashes and shared national ambitions, underpins his career. Renowned for razor-sharp receives and court-spanning reflexes, Yaku’s skills draw awe from rivals: Bokuto deems them "bone-chilling," while his relentless digs against Karasuno’s spikes ignite a mutual rivalry with Nishinoya. During Tokyo Qualifiers against Nohebi, Yaku sacrifices his ankle mid-air for a critical save, entrusting Shibayama with his role as Nekoma secures victory. Post-recovery, he reclaims his defensive throne at nationals, devising protective formations for Kenma against exhaustion tactics. Post-graduation, Yaku ascends to Russia’s Tigr Ekaterinburg and represents Japan at the 2021 Olympics. His career balances rigorous coaching with off-court levity—snacking on stir-fried vegetables, avoiding horror films—while maintaining bonds: sparring with Kuroo, strategizing with Sugawara, and cementing a legacy of defensive brilliance and team devotion.