Played by Yokoyama Kazutoshi 横山一敏
Not much is known about Kou at this point but he works for Gamou as his secretary and acts as his bodyguard, and has exceptional fighting skills. His first appearance has him defeating a squad of Foundation X members while holding a pair of walnuts in his right hand. Gamou has him go to Kyoto to help out Hayami with destroying the four pillars. He makes his first appearance to the Kamen Rider Club while at the second pillar. He easily distracts both Fourze and Meteor while Libra destroys the second pillar.
Kou helps Gotou to improve his abilities as the Capricorn Zodiarts in order to find the Core Switch. He also gains the Horoscope Switches of Scorpion, Cancer, and Aries and fights Meteor twice with them. He easily beats Meteor with them the first time but the second time, he was beaten due to him creating a weak point on his right ankle. Kou attacks Gentarou after touching Gamou so causally and easily beats him even though in a blind rage.
Human form is introduced in Kamen Rider Fourze 33.
Kou has a serious type of personality and very protective of Gamou. This protectiveness is probably his greatest weaknesses as he attack Fourze for touching Gamou so casually and recently with Hayami doubting Gamou. He settles arguments with his fists. Kou has a serious dislike of Hayami and mocks him at every chance he gets.
Previous Zodiarts: Unknown
Currently Leo is the strongest Zodiarts. He has claws along with a roar that can send people back. He is able to deflect all of Meteor's attacks along with Meteor Storm Punisher with ease. He is also capable of using other Horoscope Switches like Scorpion, Cancer, and Aries and amplify their abilities.
- The actor also does the stunt work for Leo Zodiarts.
- Tatsugami is sort of like Tategami/Mane 鬣 like a mane of a lion. And Kou 吼 means Roar.