Okada Izō(岡田 以蔵?, February 14, 1838 – June 3, 1865) was a Japanese samurai of the late Edo period, feared as one of the four most notable assassins of the Bakumatsu period. He was born in Tosa to the gōshiOkada Gihei, who had been a peasant but had bought the gōshi rank. Izō and Tanaka Shinbei were active in Kyoto as assassins under the leadership of Takechi Hanpeita.
In manga and anime, Nobuhiro Watsuki based the character Kurogasa Udō Jin-e of his manga series Rurouni Kenshin on Izō; the author admits that the character bears little resemblance to Izō.Hideaki Sorachi also based Nizo Okada, a character in his work Gintama, on Izō. It is also possible that a character from One Piece, Izô, commander of the 16th division of the Whitebeard Pirates, is based on Okada Izô. This, however, remains unconfirmed by the series' creator, Eiichiro Oda.
Masami Kurumada, author of the popular Saint Seiya manga series, more recently added a character to his work, called Capricorn Izō, who is inspired by Okada.
Okada supposedly appeared as well in Kengo, a video game based on 9 legendary swordsmen.