|Robot||Created Aphrodite A|
|Affiliation||Photon Power Laboratory|
|Family and Relations||Sayaka Yumi|
|Voice Actor||Hiroshi Naka|
|First Appearance||Assault! Count Brocken|
AppearanceEditProf. Yumi's appearance in Shin Mazinger is based on his appearance in Mazinger Z, dark brown hair, moustache, and brown eyes. His usual clothing consists of a white lab coat, a yellow shirt, a black tie, dark gray pants, and shoes.
Prof. Yumi is a good natured man towards both his daughter and Juzo's family, wishing to support Juzo's grandchildren Koji and Shiro Kabuto he offers whatever advice and assistance he can. He refuses to let the works of the Photon Lab such as Photonic Energy or Super Alloy Z fall into the wrong hands, even attempting to blow up the lab in order to prevent such a catastrophe.
Prof. Yumi is a brilliant scientist in the field of robotics, building the Aphrodite A from some of Juzo's old notes. He also completed the secret modifications to the Photon Lab started by Prof. Kabuto to make the lab into the Photon Power Fortress.
Prof. Yumi appeared in a transport plane as the Mazinger Z fought the Garada K7 and Doublas M2. As Juzo succumbs to his injuries, Prof. Yumi mourns his death before witnessing Koji go on a rampage through Atami in an attempt to kill Baron Ashura. Prof. Yumi tries to talk Koji out of it, to no avail and it is only after the Aphrodite A jumps in the way of a Breast Fire that Koji stops.
After Koji is arrested, Prof. Yumi and Sayaka notice that the Atami police force is bigger than it is supposed to be. After Koji and Sayaka escape from Baron Ashura, Prof. Yumi is relieved and starts to work closely with Tsubasa Nishikiori and the Kurogane House in preparation against Dr. Hell.
For most of the series, Prof. Yumi played little of a role in the series until the final battle with Dr. Hell. As Viscount Pygman tricked the Professor into unlocking the barrier to attack the Photon Lab, Prof. Yumi had the lab self-destruct. Both the professor and Pygman survived and Pygman was about to kill Prof. Yumi until he was helped by his daughter in the Venus A. After Pygman was killed off, Prof. Yumi revealed the hidden form of the lab, the Photon Power Fortress. Using its cannon to destroy Count Brocken, Prof. Yumi and Tsubasa focused it on an approaching Bardos before the Hell King Gordon appeared with Fortress proving to be useless against it. When everything looked lost Prof. Yumi witnessed a comeback with Gamia Q3 reversing the polarity of the Photonic Energy and Mazinger Z using the 100 Rocket Punches beforing seeing the Mycenae Empire come out of the ground.