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Kamen Rider Wiki
Icon-blade.png This article is about a/an character in Kamen Rider Blade.

Kotaro Shirai (白井虎太郎 Shirai Kotarō) is a twenty-three year-old aspiring writer, helping Kazuma and Shiori's mission by giving them hospitality. He loves to drink milk.


Kotaro Shirai is the younger bother of Haruka Kurihara and uncle of Amane Kurihara was a young man chasing the Kamen Rider urban legend on the internet. He quit his job from a publishing company and sought to become famous as a non-fiction writer.

While chasing the rumored Kamen Riders, he arrives at Kazuma Kenzaki's apartment and lets him live in his own house under th condition that he will be interview him for his story. After BOARD headquarters was destroyed, Shiori Hirose also moved in and the three began living a communal life.

In addition to interviewing, he also supports the Riders' battle by telling Kenzaki about the appearance of the Undead. Therefore, he was often involved in a dangerous situation, but he continued to support him without running away.


Although his personality is a little light-hearted and drinking milk very seriously, Kotaro is mostly innocent and serious. He cherishes his sister Haruka and niece Amane Kurihara very deeply, but often worried that Amane's misbehavior towards him. He is timid and unreliable because he is not good at cockroaches, mantis, thunder, and earthworms.

Kotaro was initially hostile towards Hajime Aikawa, who lived with Haruka and Amane, and when he finds out that he is Undead, his hostility towards him further increased, despite the fact that he had feelings for Miyuki Yoshinaga, who was revealed to be the Orchid Undead, despite the latter didn't recuperate his feelings. Kotaro's hostility appeared to deceased overtime, realizing Hajime really was a good person, which made him believe Miyuki could've been the same.

Behind the scenes


Kotaro Shirai is played by Terunosuke Takezai (竹財 輝之助 Takezai Terunosuke).


To be added.


Icon-blade.png Kamen Rider Blade
BOARD Rider System Users
Primary: Kazuma Kenzaki - Sakuya Tachibana - Mutsuki Kamijo
Keroberos Riders (Movie exclusive): Junichi Shimura - Natsumi Miwa - Shin Magaki
Gear: Blay Buckle - Garren Buckle - Leangle Buckle - Rouzers - Rouze Cards - Rouze Absorber - Chalice Arrow - Wild Slasher - Glaive Buckle - Lance Buckle - Larc Buckle
Rider Machines: Blue Spader - Red Rhombus - Green Clover - Shadow Chaser
Hiroshi Tennoji - Kei Karasuma - Shiori Hirose - Yoshito Hirose
Jacaranda Cafe
Kotaro Shirai - Haruka Kurihara - Amane Kurihara
The Undead
Joker: Hajime Aikawa - Junichi Shimura - Kazuma Kenzaki (post-series)
The Royal Club:

♠️ Spade: King - Takahara - Yazawa

♦️ Diamond: Kanai - Azumi - Isaka
♥️ Heart: Kamata - Miyuki Yoshinaga - Shinmei
♣️ Club: Noboru Shima - Hikaru Jō - Daichi
Category Ace:

Beetle Undead - Stag Beetle Undead - Spider Undead - Mantis Undead - Kerberos

Category 2-10:

♠️ Spade: Lizard Undead - Lion Undead - Boar Undead - Locust Undead - Deer Undead - Trilobite Undead - Buffalo Undead - Jaguar Undead - Scarab Undead

♦️ Diamond: Armadillo Undead - Frog Undead - Pecker Undead - Whale Undead - Firefly Undead -Tortoise Undead -Bat Undead - Zebra Undead - Chameleon Undead
♥️ Heart: Human Undead - Hammerhead Undead - Dragonfly Undead - Shell Undead - Hawk Undead - Plant Undead - Moth Undead - Camel Undead - Centipede Undead
♣️ Club: Bee Undead - Mole Undead - Rhinoceros Undead - Cobra Undead - Polarbear Undead - Jellyfish Undead - Scorpion Undead - Squid Undead - Tapir Undead
Other: Darkroaches - AlbiRoaches - Titan - Mold Undead - Jashin 14 - Trial B - Trial D - Trial E - Trial F - Trial G