Tatsuki Washio is a tall third-year student at Fukurōdani Academy and the boys' volleyball team's middle blocker. Standing approximately 187-188 cm, he possesses an intimidating appearance with slicked-back dark hair, thin eyebrows, and a straight nose; his presence once made a child cry upon first meeting. Washio embodies the strong silent type, speaking minimally but offering valued words of wisdom or encouragement to teammates. He maintains calm composure under pressure, projecting confidence in his team's collective strength, such as when reassuring others during the ace Bokuto's mood swings. Washio prioritizes focusing on his role without seeking attention. On the court, Washio demonstrates solid all-around abilities, excelling particularly in blocking and jump serves. His high school statistics rate power, stamina, game sense, and technique at 4 out of 5, with jumping and speed at 3 out of 5; his jump reach is 335 cm. Post-timeskip, his blocking skill is rated 9 out of 10, reflecting his proficiency in reading opponents and executing stuff blocks or one-touches. Acknowledged as Fukurōdani's strongest blocker, he can shut down powerful spikers like Wakatsu Kiryū. His serves are powerful and disruptive, though versatile blockers like Kuroo present a challenge. Washio typically executes straight spikes and isn't primarily relied upon for complex attacks. During the Spring High National Tournament semifinal against Nekoma, Washio starts as middle blocker, contributing significantly to Fukurōdani's defense. He closely observes opposing setter Kenma's form, though initially unable to block some spikes. Later, he wins a joust against Lev and remains wary of the rookie's evolving abilities. When Bokuto struggles, Washio shares the team's annoyance yet maintains focus. His performance includes successful blocks and powerful serves that pressure opponents. Washio's belief in Fukurōdani's collective strength provides stability, like when he voices confidence in the team during Bokuto's low points. After high school, Washio joins EJP Raijin, a Division 1 professional team in Japan's V.League, continuing as a middle blocker alongside former rivals Rintarō Suna and Motoya Komori. Within Fukurōdani, his relationships are positive; he interacts supportively with teammates, offering reassurance to setter Akaashi during high-stakes matches. His favorite food is yellowtail teriyaki.