This article is about a/an character in Kamen Rider Zero-One.

"Gai, you can't be satisfied with only 100%. You must be a man who strives for 1000%."
―Ikkei lecturing his son[src]

Ikkei Amatsu (天津一京 Amatsu Ikkei) is the strict father of Gai Amatsu.


Gai being told by his father to return Thouser after receiving a 99% test score.

When Gai was 11, he owned an AI dog named Thouser, but his harsh father was angered by his 99 percent test score, which forced Gai to return it to secure his education.


As the father of Gai Amatsu, he was very strict with his son as he was disappointed at Gai for his nearly perfect score of his exam due to his son's obsession with his robot dog "Thouser". Even though Gai studied hard to get his exam with perfect score, he was still mad to Gai about his 99 percent test score and he demand Gai to return Thouser.

Behind the Scenes


Ikkei Amatsu is portrayed by Kosei Kato (加藤厚成 Katō Kōsei), who is best known for playing Hajime Yamaoka/Mitsuhiko Ishibori/Dark ZagiIcon-crosswiki.png in Ultraman NexusIcon-crosswiki.png and Mitsuhiko HirukawaIcon-crosswiki.png in Ultraman MebiusIcon-crosswiki.png.


  • Like his son, the second character of his first name Kyo () is a numeral character which means 1016 in Japanese.


  • Ikkei's strict parenting with Gai can be seen as a type of tiger parenting, where parents consistently push and pressure their child in attaining high levels of academic and/or extracurricular achievement, usually through authoritarian methods. Children raised this way usually portray elements of chronic mental health issues, which aren't entirely absent in Gai's character.



Icon-zero-one.png Kamen Rider Zero-One
Kamen Riders
Soreo Hiden - Aruto Hiden - Isamu Fuwa - Yua Yaiba - Jin - Horobi - Ikazuchi - Naki - Gai Amatsu - Ark - S
Movie-exclusive: Soreo Hiden - S - Bell - Kamen Rider Abaddon - Leon Arkland - Kamen Rider MetsubouJinrai (Jin, Horobi, Ikazuchi & Naki)
Stageshow-exclusive: Azu - Little Assassin
Hiden Zero-One Driver - A.I.M.S. Shotriser - MetsubouJinrai Forceriser - Zetsumeriser - ZAIA Thousandriver - Cycloneriser - Raidriser - ZAIA Slashriser - Ark Driver - Hiden Zero-Two Driver - Zetsumetsu Driver - Eden Driver - Abaddoriser - MetsubouJinrai Driver
Progrisekeys - Progrise Holder - Progrisekey Connector - Hiden Risephone - Rider Models
Attache Calibur - Attache Shotgun - Attache Arrow - Breaking Mammoth - Giger - Buaruku Sabers - Authorise Buster - Assault Grip - Thousand Jacker - Progrise Hopper Blade - ZAIA Spec - Knuckle Demolition - Nihon Ookaminotsume - Claw Assault
Hiden Intelligence: Korenosuke Hiden - Soreo Hiden - Jun Fukuzoe - Sanzo Yamashita
Humagears: Izu - Shesta - Soreo Hiden - Wazu Nazotoku - Subaru - Hakase Bot - Fukkinhoukai Jiro
Legend Riders: Sougo Tokiwa - Geiz Myokoin - Woz - Tsukuyomi
Humans: Norio Uozumi - Go Sakurai - Satoshi Sakurai - Choichiro Ishizumi - Seiji Tazawa - Satō - Yuta Yomura - Isao - Shinya Owada - Ikkei Amatsu
Humagears: Mageana - Ikkan Nigiro - Anna - Mashirochan - Dr. Omigoto - Z #5 - Delmo - Love-chan - Midori
A.I.s: Zea - Zat - Ai-chan - Thouser
Ark - Horobi - Naki - Jin - Ikazuchi - Little Assassin - Azu
Monsters: Berotha Magia - Kuehne Magia - Ekal Magia - Neohi Magia - Onycho Magia - Vicarya Magia - Gaeru Magia - Mammoth Magia - Dodo Magia - Arsino Magia
Footsoldiers: Trilobite Magia - Dodo Magia Chick - Battle Magia
Other Villains:
Finis - Will
Gai Amatsu - Williamson Yotagaki
ZAIA Spec Representatives: Rentaro Tachibana - Tatsumi Arayashiki - Naoto Ichimori - Takeshi Homura - Masamitsu Yuto
Other: Daiki Kyogoku
A.I.M.S.: Isamu Fuwa - Yua Yaiba - Naki - Eida - Ono - Degawa - Shida - Eifuku - Ito
Monsters: Crushing Buffalo Raider - Splashing Whale Raider - Dynamaiting Lion Raider - Storming Penguin Raider - Scouting Panda Raider - Fighting Jackal Raider
Footsoldiers: Invading Horseshoe Crab Raiders
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