Machio Naruzo (街雄 鳴造, Machio Naruzō; "Naruzo Machio") is a personal trainer at Silverman Gym who regularly coaches the main characters from Koyo Women's Academy.
Machio is a tall man who has short black hair and blue eyes. He has a handsome face. He is always seen is a blue tracksuit. Although he appears to be slender when wearing his tracksuit, when he does a bodybuilder pose, his tracksuit ends up torn to pieces and he is revealed to have a very well-built body.
Machio is a generally nice guy who is dedicated to help the members of the Silverman Gym better themselves. When Hibiki asked him if he would laugh at her after she is barely able to complete three sets of bench presses, he answers that he cannot laugh at someone trying their best. He is noted to have a charming personality and he is very knowledgeable about bodybuilding and exercise.
Machio's running gag involves him doing a bodybuilder pose with his tracksuit bursting to pieces, revealing his well-built body. He appears to be ignorant of how much his body freaks people out. He also has apparently no shame about being almost naked in public.
Little is known about Machio's past, but, it is known that he has been incredibly buff since high school, due to being a member of the football team.
Machio appears when Hibiki tries to leave the Silverman Gym due to the too many macho men training there. She immediately changes her mind when seeing him and develops a crush on him because of his good looks.
As his physique would imply, his strength is leagues above the average human. He is able to effortlessly tear through his clothes simply by flexing. He is also able to chose whether a piece of his body or his whole body flexes to tear through his clothes.
Sakura Hibiki: One of the students from Koyo Women's Academy whom Machio coaches. Hibiki has a crush on him but he is oblivious to her infatuation towards him.
Soryuin Akemi: One of the students from Koyo Women's Academy whom Machio coaches. The two usually explain workouts and diets.
Tachibana Satomi: A history teacher from Koyo Women's Academy whom Machio coaches. Like Hibiki, she has a crush on him.
Uehara Nana: Nana is an old friend of his from High School.