Kanna

Kanna (神無, kami mu) is the first detachment of Naraku. She appears to be a ten-year-old girl with pure white hair with white clothing. As a "concealed incarnation" of Naraku, Kanna has no scent and no demonic aura, making her undetectable to InuYasha's senses and is also immune to demonic aura-related effects such as the Hakurei-zan barrier. Kanna is the only incarnation that Naraku trusts with important information about his actions, allowing her to give orders in his place. Even though she is a void, she still has her own emotion of sadness that she cannot express.

Powers and Abilities
Kanna carries a mirror that can steal the souls of those reflected in it. Once a soul is trapped by her mirror, Kanna can control that person's body to carry out her bidding. However, the mirror can be overwhelmed by an especially powerful soul such as Kagome's. It can't steal souls from those who wear powerful items such as the Celestial robe. The mirror can also create a glass demon to copy the abilities of whatever it reflects, though Kanna herself suffers damage when the glass demon is wounded.

Name Meaning
The 神無 Japanese language word meaning "godless world". Which seems to match since she is Goddess of Void.(Megami no Mu)

First Appearance
In the manga, Kanna first appears in volume 15, scroll 8 "The Mystery of the Wind Witch", page 152. There, Naraku tells Kagura "I have already sent your elder sister ... Kanna.". Then Kanna is seen walking with her mirror and some Saimyōshō towards a village, where she will steal the souls of the inhabitants and turn them against InuYasha and his friends.

Tsubaki and Musou Arc
After her appearance she uses her mirror to spy on various things for Naraku while Kagura does the work.

Shichinintai Arc
She was ordered by Naraku to give orders to the Band of Seven.

Akago Arc
While the rest of her siblings chose to betray Naraku. She was the one who stayed behind with him. She felt sorry for Kagura because she has no real freedom. After Hakudoshi's and Kagura's death and Byakuya's creation, she was order by Naraku to pretend to help Moryomaru. In which Naraku knew Akago couldn't read her mind due to her status as Megami no Mu. As more and more of her siblings demise, she started to have more sadness in her heart.

Kanna's End
It becomes clear that she was fated to die by Naraku when she finally started to express her emotions. In chapters 478 of InuYasha (Kanna's Gravestone), Kanna becomes more dangerous than anyone expected. She battles the group using a glass demon that came from her mirror. The glass demon copies the power of Tessaiga, robbing it of nearly all of its powers, including the Kaze no Kizu, Crimson Tessaiga, the Dragon-Scale power, and the Kongosōha, leaving the real Tessaiga nothing more than an apparent shell. It also appears that if the glass demon is hurt, the injuries are inflicted on Kanna since a black mark appeared on her neck after Kagome's arrow struck the glass demon in the same place with no apparent effect on it, and the same thing occurred when InuYasha struck the glass demon's left shoulder, which turns the demon into a fighting voodoo doll.

When the group finds Kanna, she fires a ray of light from the sky down at InuYasha. He reflects it with Tessaiga back at the glass demon. Kanna continues to receive damage to herself and the Tessaiga cracks from all of the light blasts. Kagome deduces that Kanna was ordered by Naraku to sacrifice her life in order to break Tessaiga.

Because she continued to take most of the mirror demon's damage, Kanna indirectly loses her left hand and right arm during the battle. In chapter 480, she was forced to die at Naraku's command, by shattering herself and the glass demon into hundreds of shards. A shard manages to hit Kagome's right eye and through the shard, Kanna communicates to her the secret to defeating Naraku.

Other than that, Kanna has never shown signs of betrayal to Naraku and was his most loyal, trustworthy detachment.

Naraku had commented upon Kanna's death that she had no thoughts and feelings; it was assumed that she did not care about either living or dying. However, after Kanna had communicated with Kagome just prior to her death, Kagome stated Kanna did not want to die and had feelings of her own. Kagome continues her ambition and finally allows the Goddess of Void to rest in peace.