A powerful Yazuka boss in Japan, Oni Juuma moved to the United States to become an equally powerful crime boss there. He was captured along with many other crime bosses by the Green Hornet. He spent the rest of his life in jail until finally dying in prison.
He is succeeded by three children - Hirohito, Kenji and Katsuko. He named Hirohito as head of the family.
It was then revealed that Oni was not dead and in fact released from prison after making a deal with Mayor Scanlon of Century City. The deal involved releasing Oni and giving him and his son the identity of the Green Hornet in exchange for helping Scanlon's re-election bid by creating the Black Hornet and reminding the public of Scanlon's past achievements.