Ogami Itto seemed to have a very cushy life during Edo-Era Japan, for he had been the Shogun's official executioner (Kogi Kaishakunin). A position so powerful, the term "Second" meant that Itto was only second to the Shogun as far as metering out death to unloyal feudal lords throughout the 60 regions of Shogunate controlled Japan. In fact, the Shogun's symbol of the Hollyhock crest was a noticeable part of Ogami's court attire, thus deeming his stature as indeed being the Shogun's final say over his people. The Kogi Kaishakunin was highest of the three positions given to certain clans of samurai under the Shogun to root out corruption amongst the feudal lords who answered to his Highness about the land. The second clan was the Yagyu who assassinated anyone caught doing treasonous deeds. The third clan was the Kurokawa. Shinobi (ninja) sent to spy on daimyos (lords) and report back to the Shogunate.
Ogami won his exulted position, by protecting his Highness during the contest to choose the Executioner. The opponent, Gunbei Yagyu, disarmed Itto but blatantly pointed the tip of his sword at the Shogun in his victory over Itto. Ogami seeing this as a direct threat to his Highness stepped in between the sword and the Shogun and thus won the slot of Kogi Kaishakunin. This did not bode well with the ancient patriarch of the Yagyu, Lord Retsudo. Angered that his son lost on a technicality, he plotted against Itto and eventually set off the events that would transform the Shogun's executioner into the assassin known as Kozure Okami (Lone Wolf and Cub).
Returning home from work one evening, Itto finds his pregant wife Azami more fragile than she should be. It seems Lady Ogami has been suffering from terrible nightmares as of late, that the men Itto put to death were cursing the Ogami line. Ogami comforts his wife by explaining if the child they were expecting was a boy, why he chose the name Daigoro. Sadly, Azami's premonition comes true as she is murdered the next day. To further destroy Itto politically and literally, a death tablet bearing the emblem of the Hollyhock crest is placed in the shine he built to pray for the people he was required to execute.
And this is where things fall apart, finding his wife dead (and Daigoro cut out of his mother's womb), Itto is devastated. The next morning, the chief inspector of the region (a Yagyu named Bizen), reveals to Itto that he is being tried for treason again his Highness, because of the blasphemous memorial tablet rumored to be in the Ogami memorial shrine. Itto-completely perplexed by such an accusation-agrees to let Bizen investigate the rumor, only to find that there is such a tablet in the shrine!
While Bizen expects Itto to accept his fate of seppuku and slay both himself and his newborn son, Ogami soon smells a rat and realizes that the Ura Yagyu (the shadow Yagyu clan led by Retsudo) are behind this plot to undo him. After he refuses to kill himself and his son, Itto proceeds to cut through the Yagyu guards sent to ensure that Ogami follows the order through. Instead, a deal is made between Retsudo and Itto; a quick battle to decide if Itto will live outside of the region of Edo, or die right then and there, Ogami swears vengeance on the Yagyu clan and thus takes his son into Meifumado (Hell). Becoming an assassin and leaving his official samurai life behind, Itto can strike back at his most hated foes and eventually bring down the clan who murdered his wife and ruined his House.
For 500 gold pieces and the condition that every aspect of why the employer wants the assassination done, Itto now known as Kozure Okami, sets about bringing his own brand of justice to the realm, all the while teaching Daigoro what it means to be samurai. And what a journey it is. Pushing his son around Japan in a souped up wooden, metal and bamboo baby cart, it's a strange and loving testament between father and son.
There is little autobiographical data on Itto save for the following: He claimed he was from the Sakushu region of Japan, has served the Shogun for 27 years, and is a master of "suemono giri" (cutting through stationery objects). Another note: his name might not really be a name but the title "sacred sword" which almost sounds like a translation of his name.