This page describes the bio-boosted Koji Kabuto of MazinSaga. For other versions of the character, see Koji Kabuto (Disambiguation).

Koji Kabuto
Koji with Z
Kanji 兜 甲児
Kana かぶと こうじ
Gender Male
Age (Young Adult)
Robot Z
Affiliation FUJI
Family and Relations Unnamed Father
First Appearance MazinSaga Chapter 1
Koji Kabuto (兜 甲児 Kabuto Kōji) is the main protagonist of MazinSaga, and is the primary user of the bio-armor Z.


Koji is much more serious and dark compared to his original counterpart. While a little hot-tempered at first, he becomes much more quiet as the series goes on. This is partly due to the great amount of regret he has for going out of control when first wearing Z and caused the destruction of Earth. In order to make amends, Koji wears the Z armor to fight against threats of the Mars colonies.

He sleeps naked and once slept with Sayaka Yumi. Over time, Koji falls in love with Sayaka and worries about her especially when he found out that Sayaka is the reincarnation of a girl that loved Koji and committed suicide during Z's rampage.


In addition to Z, Koji's strength and endurance has increased to superhuman levels when he first came to Mars, due to Mars having a 1/3 of the gravity on Earth. Due to this adaptation, he has 3 times the muscle strength and blood of a human born on Mars.


After coming home from class, Koji finds his late father's research papers and the fruits of them, Z. Koji puts the helmet on but when he sees his girlfriend being raped he is overwhelmed by Z's immense power, causing Z to go on a rampage and destroy the Earth. Within Z's subconsciousness Koji meets what appears to be his father. Koji's father releases his son from Z's influence. Koji then hears a voice and sees an angelic being before he and Z are brought to Mars in the future.

Koji wakes up seeing a robot piloted by a girl who looks like the angel, Sayaka Yumi. Sayaka and her Aphrodite A are under attack by the Garada K7. Koji uses Z's power without succumbing to it and destroys the Bio-Beast. Sayaka, thankful to Koji allows him to live on the Mars base. She explains the events of how humanity came to settle Mars after Z went on a rampage. Koji felt guilty and decided to make amends for his weakness. Through his efforts with Z, Koji became a lieutenant of the army protecting the colonies. He would fight against several enemies including God Kaiser Hell and his minions. Eventually Koji fights against Hell's grandson, Akira Fudo wearing the Devilman X armor with the threat of an alien fleet approaching as well. The manga was discontinued after this, leaving Koji's ultimate fate up to discussion.

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