Gennosuke Yumi
Kanji 弓 弦之助
Kana ゆみ げんのすけ
Gender Male
Age (Middle Aged)
Robot Created Aphrodite A and Diana A
Affiliation Photon Power Laboratory
Family and Relations Sayaka Yumi (Daughter)
Voice Actor Jōji Yanami
First Appearance Mazinger Z episode 1 (anime)
Mazinger Z chapter 1 (manga)
Professor Gennosuke Yumi is a scientist heading the Photon Power Laboratory after the retirement and later death of Dr. Juzo Kabuto. Prof. Yumi once worked under the professor and was inspired by his designs to create his own robot, Aphrodite A. Later with the Aphrodite's destruction Prof. Yumi and other scientists replaced her with Diana A. Both robots were piloted by Prof. Yumi's daughter, Sayaka Yumi.


Prof. Yumi is a middle-aged man with dark hair and a mustache. He wears glasses and at the Photon Lab he usually wears a white lab coat over a shirt and tie. For other occasions he wears a blue suit.


Prof. Yumi is a calm and collected individual dedicated to his work as a scientist. The attacks from the Mechanical Beasts have him act as the adviser to the Science Lab's pilots, doing the best he can for the pilots. Prof. Yumi can also be rather stubborn and strict with his works, refusing to upgrade Aphrodite A with additional weaponry other than the Oppai Missile System despite his daughter's constant pleas as he designed Aphrodite to be a peaceful machine compared to the more militaristic goals of his adversaries.

Prof.Yumi and Koji

In certain crises such as the government demanding that Prof. Yumi turn over the Photon Power Laboratory after being threatened by the Underground Empire or being held hostage, Prof. Yumi refuses to give in and takes action that would have even included his own death if he was not saved by Koji and the others. When defeat seems inevitable, Prof. Yumi takes drastic and sometimes questionable measures: Prof. Yumi was prepared to commit suicide rather than leave the institute like a captain choosing to go down with his ship.

However in spite of all of this, when it came to is other responsibilities, Prof. Yumi was less than satisfactory. This includes his role as a parent as well as a regular citizen; neglecting a normal life in favor of his career.


Sayaka YumiEdit

Prof. Yumi has been Sayaka's only parent since her mother has never been seen or mentioned. Prof. Yumi gives Sayaka and her allies advice when in battle, which Sayaka usually listens to. But even though they are close, Dr. Yumi does not always agree with his daughter, at first refusing to let Sayaka fight or make improvements for the Aphrodite A. As a matter of fact, due to the situation they are in Prof. Yumi even neglects his daughter's needs most of the time including when she was depressed. It was only near the end of the battle with the Mycenae Empire that Prof. Yumi actually considered not letting Sayaka sortie because of the threat of death.

Koji and Shiro KabutoEdit

With Dr. Kabuto's death, Prof. Yumi filled in the part as a father figure towards his grandchildren. While Koji does respect Prof. Yumi, his impulsiveness usually causes him not to listen to his advice. Prof. Yumi usually just lets Shiro does what he wants, confident he does not do anything too bad.

Juzo KabutoEdit

Once working under Dr. Kabuto as an apprentice, Prof. Yumi had a great respect for the late scientist. With Dr. Kabuto's death, Prof. Yumi took it upon himself to look after his grandchildren and the legacy Dr. Kabuto left behind with Photonic Energy and Japanium including the Mazinger Z. Because of this, he wants those materials to be used for peaceful means rather than warfare, hence why his initial creation had no offensive capabilities.

Photon Lab Staff Edit

As director of the lab, Prof. Yumi takes great strides to ensure everything works well. His coworkers including the three scientists also have faith in his abilities. Due to limited talk between him and Boss, Prof. Yumi usually just thanks him for his role as a scout.

Abilities and Equipment Edit

As the director of the Photon Power Laboratory, Prof. Yumi has access to most of the files, projects, and staff of the institute often going to his co-workers for advice to improve the lab and equipment as well as offer knowledge on important events related to the present. He is an accomplished scientist in his own right, using his mentor's research on Alloy Z and Photonic Energy to create robots like Aphrodite A and Diana A. Prof. Yumi is also a skilled planer and strategist, using observations and insights of possible events. This includes creating spare parts for Mazinger Z and memorizing the plans to the Jet Scrander in the event they were stolen.


Prof. Yumi witnessed the Mazinger Z's appearance and the robot protecting the Photon Power Laboratory from a couple Mechanical Beasts. As Koji joined the lab with the Mazinger, Prof. Yumi would provide advice to him and Sayaka in battle. When at dead ends, Prof. Yumi would often travel to meet with other scientists to improve the situation. During Great Mazinger and Grendizer, Prof. Yumi had very small roles but offered crucial advice during battles.


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