Kuroko

Alongside Hattori Hanzo, Kuroko will perhaps remain as the most feared Iga Ninja in the history of Kunio. Whenever the Iga felt that there was the slightest chance of defeat in the midst of a battle, they would flee, unleashing the hungry beast known only as Kuroko. No matter how many of the opponent were, no matter how strong the opponent, Kuroko would always be the last to be left standing. Never would he hold a weapon, always preferring to crack bones and rip flesh with his very own hands.

Kuroko was Hattori Hanzo's most loyal soldier, as well as his most well hidden secret. Wherever Hanzo was, Kuroko would be lurking in the shadows, unseen. During his rise to power, Hanzo had utilized Kuroko more than once, to get rid of useless Iga.

In realtiy, Kuroko was the only living blood relative of Hattori Hanzo, despite the fact that they were only half-brothers. Kuroko, who had been born of the same Warlord as Hanzo, had been beaten since an early age. Many a time he would spend the night hiding in the attic or other such unruly places. As a result, Kuroko, who was naturally small in size, would learn survival, killing with his hands, eating what he could. Spending too much time in the dark would radically alter his features, and when he did show his face, all who saw would run away, screaming.

When Hanzo eventually killed their mutual father, Kuroko would step out from the shadows, finally free of the pain that the Warlord had given them. Hanzo would be the only he had ever known to take care of him, and a bond was instantly born.

Kuroko would become Hanzo's most trusted agent, used many times throughout the war. In the end, Kuroko would die at the hands of Kibagami Genjuro, during a botched assassination attempt.