Hiruta is a middle aged man with dark hair, wrinkles, sleek eyes, a mustache, and goatee. He is usually dressed in a white lab coat with a shirt, tie, pants, and shoes.
Hiruta strives to use his creations for his benefit, developing the robot cops to sell to the police and attempted to get help by using his connection with Seiko Hayami. But when that did not work, he decided to sell his services to Nagaiwa while faking his death to get better profit and further his research in robotics to develop robots with the capabilities of humans.
Hiruta is a roboticist able to develop humanoid robots that are able to perform powerful feats and even transplant organs like the brain into a robot body. He also found a way to create a group of robots that could interact and be controlled through a leader. Hiruta's research in data and programming also allow him to transfer data from one brain to another, even if it is in another body.
Hiruta unable to get any further developments at his factory faked his death and worked under one of his investors, Muyo Nagaiwa in order to get more profits. Hiruta put Nagaiwa's brain and eyes into a robot body that Nagaiwa could control so that he could rob banks and eventually transfer his brainwaves into a new body. The body would be from Toshio Tanaka, but before the operation could commence Hiruta and Nagaiwa were interrupted by Seiko Hayami and Kyu-chan. With Seiko restrained by the robot army, Hiruta was amused by the idea of transferring Nagaiwa's mind into Seiko's body but decided to kill her first. Kyu-chan reappeared as Cutey Honey in her Mazinger Honey form taking out the robots and knocking Hiruta unconscious.