|Robot||Great Mazinger (Prototype), Great Mazinger|
|Affiliation||Photon Power Laboratory|
|Family and Relations||Jun Hono (Partner)|
|Voice Actor||Hiroshi Yanaka|
|First Appearance||A Fierce Battle! Double Mazingers|
Most of Tetsuya's background is unknown, aside from being close to his childhood friend Jun Hono and being an ace pilot. Rather than being trained to pilot the Great Mazinger, he was recruited by the Photon Power Laboratory for his reputation.
Tetsuya's appearance in Mazinkaiser is identical to his original appearance with a unique dark brown colored hairstyle. His pilot suit is usually colored red and black and wears a white helmet that partly resembles the head of the Great Mazinger. His civilian clothes consist of a blue jacket worn over black clothes and white pants.
Tetsuya is a determined fighter, confident in the power of the Great Mazinger even when the robot is badly damaged. He is willing to protect and assist the people he cares about even if it means fighting against allies like Koji Kabuto and risk his very life. He is close with his friend Jun Hono and has a begrudging respect towards Koji.
Tetsuya is an ace pilot, especially with the Great Mazinger robots. He was able to pilot the complete Great Mazinger in a small amount of time and pilot it with the same skills as its prototype. His will to fight is also a strong weapon, allowing him to fight staggering odds such as an army of Mechanical Beasts with a weakened Great.
Tetsuya piloted the prototype Great Mazinger agains the attacking army of Mechanical Beasts before getting damaged and the Mazinger Z getting captured with Koji being ejected. As another wave of Mechanical Beasts attacked, Tetsuya piloted the damaged Great in spite of warnings of his injuries and Great Mazinger's state. He manages to fend off a few Mechanical Beasts until Baron Ashura used a modified Mazinger Z known as the Ashura Mazinger to fight the Great, almost destroying it if not for the arrival of the Mazinkaiser. However, after the Kaiser took down the Ashura Mazinger; it proceeded to attack the Photon Power Laboratory. Tetsuya tried to stop it with the Great, but the Kaiser was too powerful. When Koji was seen inside the Kaiser, Tetsuya called out to Koji managing to stop the Kaiser.
As Koji woke up from the infirmary, Tetsuya was impressed with the Kaiser before deploying again to fight another wave of Mechanical Beasts despite the three scientists and Jun's insistence not to. When Aphrodite A was captured and torn apart, Tetsuya encouraged Koji to fight on rather than surrender as he had the Great destroy some of the Mechanical Beasts, especially with help from the Great Booster. As the Kaiser destroyed the Gool, Tetsuya and Jun left the Photon Power Lab for Tetsuya to recover from his injuries and repair the Great.
Later when the Kaiser is in endanger from the recently revealed Ghost Mechanical Beasts. Tetsuya comes to the rescue with the finalized Great Mazinger and the Kaiser Scrander. Tetsuya advises Koji to go fight Dr. Hell while he fights against the Mechanical Beasts. After a while, Tetsuya manages to have the Great destroy the Mechanical Beasts. At the end of the battle, Tetsuya merely smiles as he hears Koji and the Kaiser come back from Hell Castle.