2006 saw Sakaguchi in more mainstream roles, such as Yashamaru in Shinobi: Heart Under Blade, and "Grave" in Death Trance. He also guest-starred in the Japanese tokusatsu show, Kamen Rider Kabuto, as the villain Reiji Nogi/Cassisworm. In 2008, Sakaguchi made his directorial debut with Sakigake!! Otokojuku (a.k.a. "Samurai School"), in which he also starred, wrote the screenplay, and choreographed the action sequences. He made a cameo appearance in Yoshihiro Nishimura's 2008 exploitation film, Tokyo Gore Police, as well as directed/starred in Yoroi: Samurai Zombie, based on a story by Ryuhei Kitamura.