Also known as: 善法寺伊作, 伊作
A character in Rakudai Ninja Rantarou. 15 years old, 163 cm tall, gentle and caring personality, always carry a first aid kit with him, long brown hair usually kept in a Ponytail.
Isaku is a 6th year student from the the Ha-class in Ninjutsu Academy.
He is voiced by Okiayu Ryoutarou.