She is a girl created as a result of Nico Kanna's wish. She is a duplicate of Nico, with several key differences. Her life and personality were what Nico's would have been like, were it not for the the shooting incident that killed her friends when she was a child.
She started off as a regular girl. Upon finding out she was a duplicate, she made her wish to have the power to "connect" to other people without them knowing, in order to take revenge on Nico and the other Pleiades Saints, and became a magical girl herself.
Kanna is highly vengeful and manipulative, and will stop at nothing to crush the Pleiades. She deeply resents the fact that she is an artificial being, and feels a degree of camaraderie towards Kazumi, who is similarly artificial. She plans to wipe out humanity with the magical girls stored in the Freezer, as once all the real humans are gone, her artificial magical girls will be the "real" ones.
Kanna was created as the result of Nico's wish. Her life was perfectly normal, with no knowledge of Nico or the Pleiades Saints, until she witnessed them fighting Yuuri Asuka's witch. She met Juubey soon after, and was enraged to discover that her life and memories were fabricated. She made a contract with Juubey, wishing to "connect" to the Pleiades without their knowledge and take revenge on them. In doing so, she gained Nico's knowledge of Kazumi and the Freezer, as well as the Pleiades' abilities. She used the Pleiades' magic to create Evil Nuts, distributed them to Yuuri and Ayase, and sent the two girls to attack the Pleiades and kidnap Kazumi. Kanna asked Yuuri to bring Kazumi to her before the start of the story, but the accidental suitcase swap with Tachibana delayed her plans.
In Chapter 9, she introduces herself to the Pleiades as Nico after the real Nico turns into a witch, and is believed to be Nico throughout the following chapters. Jubey, a disturbing grin on his face, says that the body was Nico's "spare" and "compensation for Nico's contract". Kaoru asks why Nico didn't tell them. Nico says that to deceive an enemy, you have to deceive your allies. Kaoru punches her, then gives her a hug. Nico then says they should cut to the chase. Kaoru tells Saki Kazumi can handle it and Umika implants her altered memories into Kazumi. Kanna then takes out a container that has the Soujus, their Soul Gems, and the Soul Gem and body of another magical girl. The bodies of the magical girls have been shrunken to the point where they can be picked up by one hand. She puts the two girls into two new containers, saying they "will keep on waiting for the prince's kiss."
After Satomi reveals Kazumi the truth of Michiru and her clones, Nico is seen along Juubey, commenting that Satomi finally told it to Kazumi, revealing that she knew Satomi's plans all along. Nico collects Satomi's body and Grief Seed after Kazumi kills her witch and flees.
The Pleiades reconvene at Umika's house. Nico attempts to locate the runaway Kazumi and fails, as she is unconsciously using cloaking magic. Nico asks the others what to do about Satomi's remains and Kazumi. The consensus is that they'll kill Kazumi before she becomes a witch, and revive her and Satomi as many times as necessary. Kaoru alone objects.
Later on, Nico arrives with the other Pleiades at the Freezer, in response to Kazumi's ultimatum. Kazumi begins to transform into a monster and engulfs the room in a barrier. Nico is struck with energy blasts almost immediately and incapacitated. As Umika, Mirai and Saki battle Kazumi, Kaoru realizes that she has not actually become a witch, and is simply creating an illusion so that they'd have no choice but to kill her. As the other Pleiades stand before Kazumi in shock, Mirai cleaves her in two.
Surprisingly, Kazumi's corpse turns into a balloon-like doll of Nico, as does the Nico that she incapacitated. The real Nico steps into view, with the real Kazumi safely stowed in her collection tube. As Mirai stares, shocked, Nico directs her attention to Saki, whose Soul Gem is about to break open. Nico creates a clone of herself, which then generates an Evil Nut and presses it into her forehead. The clone is vaporized as a beam of lightning shoots up around Saki. The remaining Nico says that she can't allow "you humans" to kill Kazumi. She reveals herself to them later, taking Kazumi hostage and turning Saki into a witch with an Evil Nut, before preparing to attack them directly.
Powers, Weapons & Abilities
Kanna can tap into the powers of each Pleiades Saint and "connect" them to make new effects. One example is her ability to create Evil Nuts, which are a combination of Umika's analysis magic and Nico's regeneration magic. She can also use Nico's magic even after Nico herself dies; it is unknown whether this extends to others as well or is unique to Nico.
She can also create lengths of magical string from her hands, to directly attack and restrain enemies. They are somewhat reminiscent of a puppeteer's strings.
- Kanna refers to artificial magical girls like herself as "Hyades" (ヒューアデス), as they are the half-sisters of the Pleiades (プレイアデス) and will take over from the humans (ヒューマン).
- The marking on her Soul Gem is a pair of hexagons, identical to the one hexagon present on Nico's Gem. It also resembles the figure-eight markings on the Evil Nuts. It can also be thought of as a symbol of mitosis, pointing to her nature as a clone derived from Nico.
- For all Kanna's origins angst, the fact that Nico called herself ニ子 (possibly "Second Child") could mean that she viewed her clone as the original, as in "how it should have been", and herself as the "fake" or "second one".