Koji Kabuto
Kanji 兜 甲児
Kana かぶと こうじ
Gender Male
Age 17
Robot Mazinger Z
Affiliation Photon Power Laboratory
Family and Relations Juzo Kabuto (Grandfather),

Unnamed Grandmother, Kenzo Kabuto (Father), Unnamed Mother, Shiro Kabuto (Younger Brother)

First Appearance Unknown
Koji Kabuto is the main protagonist of the Mazinger Z manga by Gosaku Ōta, as well as a supporting protagonist in its sequels Great Mazinger and Grendizer.


Koji was raised by his grandfather Juzo Kabuto after his parents were said to have died in an accident. He lived with his grandfather and his younger brother Shiro for years. By the time Koji got into high school he met Sayaka Yumi and quickly became friends with her, he also met Boss who developed a one-sided rivalry between them (especially for Sayaka's attention).


Koji's appearance and wardrobe is mostly the same as his other counterparts, having semi-spiked black hair combed backwards with sideburns facing forward. He has black eyes and an athletic build. His clothes usually consisted of his school uniform, his pilot suit for Mazinger Z, and his pilot suit in Grendizer.


Koji is hot blooded and highly confident in his abilities and the power of Mazinger Z, often to the point of arrogance. His attitude tends to get him into trouble, something Sayaka berates Koji for especially when Koji says he doesn't need her help in some battles. However, Koji geniunely cares for his family and loved ones; not wanting to put them in danger and is willing to risk his life for them. He is highly flirtacious, trying to get the attention of any attractive girl he meets. Koji possesses a strong will, never breaking down in fear or anxiety and will accept any challenge in front of him.



Koji, having believed his parents were dead stuck close to his grandfather and Shiro. When Juzo died, Koji did everything he could to help his younger brother. By the time Koji found out his father, Kenzo Kabuto was still alive he tearfully greeted his father and was more than upset when Kenzo sacrificed himself to save everyone. He also gained a respect for Kenzo's adopted son, Tetsuya Tsurugi and agreed to fight with him to avenge Kenzo. Koji was distraught when Kenzo blew himself and the Great Mazinger up to destroy Great Marshall of Hell.

Love InterestsEdit

Sayaka Yumi is the main target for Koji's affection (and perversion), and is one of the closest people towards him. While Koji and Sayaka often argue, especially concerning the fight against Dr. Hell, they none the less care about each other with Koji not wanting Sayaka to get hurt. Sayaka in turn geniunely cares Koji and gets jealous when other girls get close to him. Other girls that caught Koji's eye included Misato who likes to play along with Koji's flirting, Hikaru Makiba who does not show much of an interest in Koji besides friendship, and Maria Fleed who shows more of an interest in Koji than the other way around.


While Koji considers Boss and his gang a nuisance because of how much they bothers him, he considers Boss a friend when Boss is not trying to get Sayaka's attention or try to outshine him. When Koji met Duke Fleed, they started off as rivals that usually argued and fought. But when Koji learned his true identity, he showed Duke a little respect while still getting in a few quarrels with him. However, when Duke showed a desire to control the world to protect it from the Vegan Empire and themselves, Koji expressed disdain for the idea and tried to talk Duke out of it.

Abilities and EquipmentEdit


Koji is a highly skilled pilot, having been riding motorcycles for a good part of his life and mastering the controls of Mazinger Z in a short amount of time. He is able to control the robot in any situation and turn the tide of battle quickly in spite of overwhelming odds with his skills plus his strong will.

Fighting SkillsEdit

When on the ground, Koji uses an unorthodox fighting style that hits the weak points of an opponent's body. He also uses a photon gun in some circumstances.


Mazinger ZEdit

Koji felt a large tremor at school and went to check on his grandfather back at his house. There he found Dr. Kabuto under rubble and helped him out. Juzo told Koji there was no point in getting help and instead directed him to his secret project, Mazinger Z. Dr. Kabuto passed away in Koji's arms while explaining to Koji about the threat of Dr. Hell and that Mazinger was meant for Koji to pilot. Koji mourns for his grandfather before getting in the Hover Pilder and docking onto Mazinger. However, Koji quickly loses control of Mazinger Z before directing the robot to the Photon Power Laboratory where it is being attacked by Mechanical Beasts. But even when Koji manages to defeat them, he still has no control. Sayaka piloting Aphrodite A, put Mazinger in a hold to stop the rampage.

Koji explained to Sayaka, her father, and Shiro what happened and they agreed to help Koji in the affair. But when Koji said he could take care of it all himself, Sayaka bopped him on the head. In the coming time, Koji would have Mazinger fight Dr. Hell's Mechanical Beasts and his lieutenants while encountering some problems such as flying Mechanical Beasts. In one incident, Koji paired up with a young man who could change into a demon called Devilman who pointed out the flaw in battle in Mazinger as Dr. Hell teamed up with the Demon Tribe. They managed to stop the threat and Mazinger could now fly with the Jet Scrander. Other times Koji would do some random activity with Sayaka, Boss, and Shiro, or even flirt with Misato.

As the battles continued, the Ghost Mechanical Beasts are introduced. But even with this new threat, Koji and the Mazinger still triumphed. As Dr. Hell was losing Mechanical Beasts, the Photon Lab decided to make a full on assault on Bardos. However, after the Mechanical Beasts were defeated Bardos blasted off into the atmosphere. After Dr. Hell escaped however, a prophet fortold of a greater evil below the surface. Hearing this from Boss, Koji thought he was just hallucinating until the Mycenae Empire surfaced. Koji and Mazinger fought with all of their might but they were badly damaged. Waking up, Koji was remade into a cyborg by his thought to be dead father. Koji tearfully greeted his father.

Great MazingerEdit

Following Koji's conversion, he and Sayaka left for the United States to study while Tetsuya Tsurugi and his partner Jun Hono deal with the Mycenae Empire. However once the Great General is dealt with, Dr. Hell comes back as the Great Marshall of Hell and begins his acts of conquest. Koji meets Tetsuya with a reinforced Mazinger Z when Tetsuya and Kenzo's group comes to the United States. He and Sayaka help fight off against threats made by the Great Marshall until Kenzo is killed when he sacrificed himself to save everyone. Mourning his father's death, Koji strikes up an alliance with Tetsuya to defeat Hell. During the battle, Mazinger is badly damaged and can't join the Great. Koji could only watch as Tetsuya had the Great self-destruct to destroy Hell for good. The battle was won, but with the loss of friends and family.


With the battle against the Empire over, Koji spends his time with the Space Science Laboratory even developing his own flying saucer to coincide with the UFO sightings across Japan. One day Koji went to the Makiba family ranch where the workers thought he was an alien before Koji introduced himself. Koji got a bit of attention and took a liking to the owner's daughter Hikaru Makiba. Koji's talk of contact with the UFOs was criticized by the ranch worker Daisuke Umon, the Space Lab director's son. Regardless of any warnings, Koji went ahead and tried to make contact with the aliens. The Vegan Empire however was anything but peaceful, and tried to attack Koji. However, he was saved by a giant robot piloted by Daisuke who regained his memories as Duke Fleed. With Duke's identity revealed, Koji spent more time at the ranch while getting into fights with Duke and trying to get Hikaru's attention (not to mention avoiding her overprotective father).

Soon as more attacks from the Empire come, Sayaka comes to pick up Koji and Duke as there was a message from the Emperor of Darkness. The message was a request for an alliance. Koji was against the idea for what the Empire did to his father, Misato, and Tetsuya. But everyone else (especially Dr. Umon) went with it as the Vegan forces were so big to fight with just the Grendizer. Koji begrudgingly went with the plan while keeping his guard up around the underground empire. As the Vegans attacked, the Emperor of Darkness held them off while Duke and Koji were sent to escort the Emperor's real body away so that the Vegans don't get to him. However, Koji in a state of mixed feelings dropped the Emperor's case which caused him to suffocate and his energy form to fade away. With the Emperor gone, the others hid for cover and survived the onslaught. While looking for a way out, Koji discovered a hidden city that Duke blew up after they managed to get out.

More attacks from the Vegan Empire came which included Koji acting as Duke's motivator when he was in a slump or becoming the Empire's prisoner. He and Duke manage to get out of danger and later even meet Duke's sister Maria after clearing up a misunderstading. However, by the time Duke starts to have thoughts on controlling the Earth to protect it from the Vegan Empire and themselves after a fallout between Duke and Dr. Umon, Koji started to be concerned with Duke as he might become a threat. Soon the fallout expands to the entire planet as the Vegan Empire was gaining a foothold in Earth's governments and Duke starts to unleash the Grendizer's full power. When the ancient machine Raaga reacts to the nuclear outbreak, Duke forces the others to follow him to stop it. Koji and Hikaru manage to disengage before both the Grendizer and Raaga enter a hiberation with their pilots. As the survivors, Koji and Hikaru leave to find the other survivors after the tidal wave took out civilization.

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