|Robot||Created Aphrodite A|
|Affiliation||Photon Power Laboratory|
|Family and Relations||Sayaka Yumi (Daughter)|
Prof. Yumi is a middle aged man with dark hair, a moustache, and glasses. He usually wears a white lab coat over a shirt and tie.
Prof. Yumi is a mild mannered man who tries to find the best possible way to handle a situation. He cares a lot about his daughter Sayaka and his mentor's grandchildren Koji and Shiro Kabuto. However when at a difficult point that looks hopeless, Prof. Yumi does some more questionable acts such as ordering a fleet of ships to cast mines into the ocean to destroy the Saluud when the Mazinger, Koji, and even Sayaka were on board to prevent Dr. Hell from getting his hands on Mazinger Z.
Prof. Yumi is a highly competent scientist able to build the Aphrodite A from some old notes of Dr. Kabuto's designs. He also formulates some plans of attack when dealing with the Mechanical Beasts, that would have the best effect possible for a situation.
Prof. Yumi witnessed the Mazinger Z going on a rampage and had Sayaka pilot the Aphrodite to confront it. Later he learns that the pilot is the grandson of his predecessor Juzo Kabuto. He learns from Koji that Juzo had died before being alerted of the Mechanical Beasts that were approaching the lab. When the lab was under attack and defences proving to be useless, the Mazinger saved the lab after gaining better use of the controls. Prof. Yumi thanked Koji and had the Mazinger placed into the lab's storage when needed while getting Koji and his brother Shiro a new home.
Prof. Yumi would usually have very small roles in the series such as advising Koji on the best possible way to fight the Grogos G5 filled with hostages. When Baron Ashura attacked the major cities of Japan, Prof. Yumi was forced to turn over Mazinger Z. With Z held in enemy hands, Prof. Yumi made the hasty choice of having a fleet of ships bomb the ocean to destroy the Saluud. Fortunately, Sayaka and Boss were able to escape. When Koji and Mazinger did not surface, Prof. Yumi spoke about a chance on how they might make it out if using the Photon Rockets on the Mazinger's feet. With an explosion, everyone thought the worst until Mazinger and Koji surfaced.
With Dr. Hell's forces becoming more of a threat, Prof. Yumi had commissioned the creation of the Mazinger Army and Jet Scrander to finally deal with Dr. Hell. While the Mazinger Army took off, the Mazinger had to wait before it could use the Jet Scrander. Prof. Yumi explained the abilties of the Mazinger Army before seeing Koji off in the final battle.