Takuya Masumoto as Masaharu Shōta, a former Boy Detectives Club member, and currently a member of the tennis club, gardening club, and judo club of Rurino Academy.
Ibuki Kido as Makoto Noro, the sole female member of the Boy Detectives Club, and a technically-minded computer expert.
Ryota Ohsaka as Kensuke Hanazaki, a boy who, in his admiration of Akechi, has wanted to join the Boy Detectives Club since he was eight years old.
Yuichiro Umehara as Ryō Inoue, the former leader of the Boy Detectives Club, before leaving the position altogether and handing it to Hanazaki.