Though he develops the Kamen Rider Birth System for humans to use Medals like Kamen Rider OOO, Maki soon became more intent on studying the Greeed.
During the events of Kamen Rider OOO: Nobunaga's Desire, Maki forcefully provides Nobunaga with the three black Core Medals to have him assume his Armored Warrior Inhumanoid's complete form.