Alumnus of Too Academy, third-year law student at the University of Tokyo. Aspiring prosecutor. Former captain of the Too Academy High School basketball team. He has squinting eyes and wears rectangular glasses. He speaks in a Kansai dialect and refers to himself as "Washi" (old-fashioned/regional). He attended Seki Junior High, affiliated with Osaka Gakugei University. He exudes a mellow atmosphere, speaking sociably even to enemies, but he is actually calculating and quite devious. He occasionally opens his eyes, revealing a sharp, unfriendly gaze with sanpaku eyes. He believes that "as long as we win, it doesn't matter who the allies are" and "victory justifies the means." He tolerated and sometimes defended the selfish behavior of the ace, Aomine, who was two years his junior and constantly caused friction within the team. He was the one who went with Coach Harasawa to scout Aomine, providing the catalyst for Aomine's enrollment at Too. Because of this, Aomine is relatively obedient to Imayoshi. While his full basketball prowess isn't frequently depicted, he possesses high-level techniques like the double clutch and buzzer-beaters, such as a three-pointer thrown at the last second that looked like a fluke (Inter-High vs. Kaijo, Winter Cup vs. Seirin). He excels at reading opponents' thoughts; Hanamiya described him as "top-tier at doing what people hate" and called him "yokai-like." During Aomine's recruitment, he saw through Aomine's frustration and longing—which looked like mere insolence to others—and called him "delicate." He is a man capable of managing eccentric and difficult personalities like Hanamiya and Aomine.

Second-year medical student at the University of Tokyo. Aspiring psychiatrist. He is handsome, characterized by hazel eyes and thin, trailing eyebrows. He attended Seki Junior High, affiliated with Osaka Gakugei University. Former captain of the Kirisaki Daiichi High School basketball team. After the previous coach resigned, he also served as the coach. He is one of the players known as the "Uncrowned Kings," alongside Teppei Kiyoshi and others. He has the nickname "Bad Boy." True to his nickname, he has a warped personality and enjoys entrapping others to make them miserable. Rather than just winning, he wants to see opponents who have staked their youth on basketball lose miserably. He directs intense rough play, such as elbows and stepping on feet out of the referee's sight, frequently injuring the opponent's ace or key players, making him a true villain. His malice was enough to make even the calm Kuroko genuinely angry, and he is one of the few people Kuroko addressed with the blunt "temee." Riko described him as "a piece of trash, the exact opposite of his name (Makoto/Sincerity)." His obsession with strategy is enough to give his own teammates the chills. He uses a finger snap as a signal to his team for the timing of a trap. As befitting an "Uncrowned King," his basketball sense is high, demonstrating three-pointers and teardrop shots. Furthermore, he possesses a brilliant mind that makes his teammate Seto (IQ 160) say "I feel like I can't win against him." In middle school, he was always at the top of mock exams without even trying.