Nanami is Shichika's older sister. She is a sickly girl who is babied by him. She is extremely intelligent and knows many things despite living on a secluded island her entire life.
Though she appears to be helpless on the surface, she is actually stronger than Shichika. In episode 4, she single handedly defeats three Maniwani head members without putting forth much effort. She reveals that she can learn how a technique works merely by looking at it, and can perfect the technique the second time she uses it. She says she is jealous of people who work hard to perfect a skill, as she has never once had to try at anything in her life. She was originally going to be the next successor of Kyotouryuu, but her father chose Shichika instead, claiming she was too powerful to be taught the style. Even so, she secretly watched her father and brother train, so she knows every technique without being taught them.
She is sick enough that she should have died at a young age, but her body refuses to let her die. She claims no pain bothers her anymore because of the pain she has gone through since her childhood as a result of her illness. As a result of her skewed view of pain, she cannot see how it affects others, which may cause her indifference to killing. Before killing Kamakiri, she tells him that she made Shichika stop biting his nails by removing them from his body.
She later leaves the island to join Shichika and Togame. Her journey includes the process of wiping out a village or two, bunch of holy guards and possibly anyone standing too close as she doesnt see killing any different to uprooting a weed. After she obtains the deviant sword Akutou Bita she proceeds to slaughter every monk at the Gokenji Temple and gets comfy waiting for Shichika.
At the end of episode 7, she was killed by Shichika and, as implied by Togame, she wanted to be killed by Shichika further implying that this is the reason she followed the two.
