School: Shiratorizawa Academy Position: Wing Spiker (WS) / Opposite (OP). Height/Weight: 189.5 cm / 84.8 kg (3rd year) → 192.7 cm / 90.6 kg (Pro, 20s). Max Reach: 345 cm. Birthday: August 13. Favorite Food: Hayashi rice. Jersey Number: 1 (Shiratorizawa), 11 (Japan National Team), etc. Personality: Extremely serious and blunt. He states facts without malice, leading others to call him "clueless" or "airheaded." Famous Quotes: "I'm Hitoka Yachi, from the concrete," "A superior sprout (Shiratorizawa) bears superior fruit. Toru Oikawa should have come to my school." Background: Following his father's (a former pro) advice, he kept his left-handedness as a weapon rather than correcting it. Even after losing to Karasuno, he hungrily pursued greater strength and took to the world stage. Sharp Eyes: Sanpaku eyes that are always sharp, conveying a strong will. Eye color is olive green (dark green). Thick Eyebrows: Distinctive, masculine, and sharp thick eyebrows. Hairstyle: Short, dark olive-brown (or black) hair. A rugged, simple style with the bangs slightly parted.

School: Inarizaki High School (2nd year). Position: Setter (S). Appearance: Blonde hair (dyed), undercut with a center part, blessed with a 183.6 cm physique. Talent: A genius known as the "High School No. 1 Setter." He is also a powerhouse server who commands both a lethal spike serve and a jump floater. Personality: Confident and insolent, with high-level provocation skills delivered in a regional drawl. However, he is more serious about volleyball than anyone, believing in total devotion to his spikers. Twin Bond: The duo with his younger twin brother, Osamu, is feared as the "Miya Brothers"; they managed to replicate Hinata and Kageyama's "Freak Quick" on their first try.

School: Inarizaki High School (2nd year). Position: Opposite (OP). Appearance: Silver hair (grey), parted on the left (opposite of Atsumu), 183.8 cm (2 mm taller than Atsumu). Talent: Possesses volleyball sense equal to Atsumu's. His skills as a setter are also top-tier, showing incredible combo play by recreating the "Freak Quick" with Atsumu. Personality: Appears calmer and more composed than Atsumu, but is just as competitive at his core. A staple of their relationship is getting into full-blown physical brawls (twin fights) during daily life or matches. Favorite Food: Loves rice; his eyes change color whenever food is involved.

School: Nekoma High School (3rd year). Position: Middle Blocker (MB). Appearance: Characteristic "rooster head" bedhead (black hair), sharp sanpaku eyes, tall at 187.7 cm. Talent: A master of the "Read Block" who perfectly shuts down opponent spikes. An all-rounder with top-class receiving skills. Personality: Usually acts nihilistic and provocative, but is a calm and cool-headed strategist. He has a caring side, often mentoring juniors from other schools (like Kei Tsukishima).

School: Nekoma High School (3rd year). Position: Libero (L). Appearance: Short brown hair, small stature (165.2 cm), with sharp eyebrows and eyes. Talent: Possesses such top-tier receiving skills that Karasuno's genius libero, Yu Nishinoya, acknowledges his ability as "terrifying." His greatest weapon is "perfect positioning," cutting off the spiking lanes before the opponent even hits. Personality: Usually the caring and kind "Mom of Nekoma," but snaps instantly if anyone mentions words related to his height (like "shorty").