Tadashi Yamaguchi

Tadashi Yamaguchi (Yamaguchi Tadashi) is a member of the Karasuno High Volleyball Club. He plays the role of pinch server in the team. Yamaguchi is a young-looking boy with an average build. He has short black hair, often portrayed as brown or even green with a flyaway piece of hair sticking up at the top. Back in middle school, he was teased for his freckles and overall scrawniness.

He seems to have grown into it now and isn't bothered about it as much. After joining the Karasuno volleyball team during games, Yamaguchi wears Karasuno's black, orange, and white uniform with the number 12 on the back. He also wears knee pads, and white volleyball shoes with black details. Outside of matches and practice, Yamaguchi wears a black gakuran, the Karasuno uniform.

Yamaguchi is a pretty shy person who relies on others. Though he is generally a nice person, he tends to snicker along or join in with Tsukishima whenever he's mocking others. He is hardworking, as shown when he sought for extra training on his own, and how he continued practicing outside of the team after seeing how weak he was compared to his other teammates. After a fatal loss in the match against Aobajōsai High, he gained a lot of confidence thanks to his teammates and Makoto Shimada since he was helping him practicing the jump float serve. During the summer training camp, he even stood up against Kei Tsukishima, who was surprised and called him "cool" for the first time. Tsukishima started working harder, and their relationship returned to normal after that event.