Chiyuki

The Black-Haired Woman (黒髪の女 Kurokami no Onna) often referred to as Onna, is an amnesiac woman taken in by Nona to Quindecim and hires her as Decim's assistant. Later, her real name is revealed to be Chiyuki (知幸 Chiyuki).

Appearance
Chiyuki is a young woman with violet eyes. She has shoulder-length black hair with a streak of white in her bangs. Her slender and semi petite figure is accentuated with a black crop top, a mini skirt held by a white belt, and ankle strap heels. She accessorizes with a necklace and a white bracelet.

Personality
Chiyuki appeared innocent but skeptical when she first woke up. However, after she became accustomed to living in Quindecim, she acted as a strong-minded individual who always says what is on her mind whenever she feels it's necessary. She does not hesitate to oppose Decim if she feels there is something wrong in what he says. Also, because she retains her humanity even when all her memories are lost, she can give valuable insights to Decim whenever he is judging.

History
When Chiyuki was young, she liked reading Chavvot with her mother –a story about a boy named Jimmy who falls in love with a deaf girl named Chavvot. She has stated that the moments when Chavvot smiles are her favorite parts.

After her death, Chiyuki became one of Decim's customers. However, unlike the other humans who had no memories when they arrived, hers were intact and she was aware of the fact that she was dead. For this reason, Decim could not provoke her into playing a Death Game and with Nona's permission, he had her memories erased and extended her judgement period. After that, she was allowed to stay in Quindecim and assist Decim in arbitrating.

It is later revealed that she was a young professional ice skater. She had a happy childhood growing up with her mother and father and after reading her favorite children's book Chavvot, became interested in ice skating after seeing the little girl in the picture book ice skate. She became very good and it became her passion. She was shown to live her life to the fullest with many great friends and with a warm loving family. Her career as a professional ice skater also began to skyrocket after she won several awards. However, this all changed when she received a horrible knee injury that took away her ability to skate. When she lost her ability to skate, she fell into depression but grew to realize it was not the fact that she couldn't skate that was so depressing so much as the fact that it was what defined her and after being unable to skate, she felt hollow and empty, as if she was nothing and all of the people she cared about became like strangers, as they did not truly understand her and because she lost the one things she could relate to with them: her ability to skate.

Death Billiards
In Death Billiards, she was simply referred to as the 'The Black Haired Woman' who quietly sits back and observes a judgement game as Decim's assistant.

Death Parade
Her role is further elaborated on in Death Parade: Because she was aware of her death, Decim couldn't judge her. With Nona's permission, her memories were erased and she was assigned the role of Decim's assistant as part of her judgement. She helps Decim understand human emotions and provides insight in passing judgements and reading people's feelings. Despite this, she disapproves of the concept of bringing the darkness out in people's hearts, as she feels the arbiters are creating them instead. Eventually, she began to remember who she was, largely due to her re-reading Chavvot, an old favorite book. As she begins to remember, her body begins to crumble, because humans are not permitted to stay in Quindecim for too long before they are judged.

Decim
The two have a close relationship. She helps teach Decim about humans and understanding their emotions and actions. It is implied he may hold feelings for her. It is even implied she may hold feelings for him, as she often looks forward to the chance to see him smile, like in episode 7, 11, and 12, and wanted to get to know him better. She was somewhat disturbed by Decim's hobby of collecting dummies until learning they were the dummies of the people he judged who were sent to the void and wanted to keep them as he felt it was wrong to dispose of them like they were nothing and because he respected how they lived fulfilled lives. She remembered how Nona said it was a disgusting hobby, but Chiyuki thought it was good because it showed he cared for those who came. She is shown to be comfortable around him, often stating her opinions on his judgements to him. She does not like how he, as an arbiter, has the customers play games that draw out the darkness of their hearts and this comes to a head with the customers Shimada and Tatsumi, as Decim forced the darkness in Shimada's heart as he chose to stab Tatsumi and go to the void rather than be reincarnated and see his sister, because Tatsumi witnessed his sister's rape and failed to help. Chiyuki angrily exclaimed that Decim had not drawn out the darkness in the customer's hearts, but instead created them. Her words were enough to put Decim's position as an arbiter, his very existence, and the method which arbiters judged their customers as wrong. He began to develop new games and ways to judge his customers that were not as harsh and extreme as before and even made sure he would be the one to judge where Chiyuki went. He complimented her in episode 11 during her judgement, saying she looked beautiful in her skating outfit and loved the way she skated, even having the dummies clap their hands at her performance using his strings. When he saw her in agony over her desire to see her mother and the need to have to sacrifice a life to do so, along with her refusal and frustration over her predicament, Decim broke down and cried, saying he wanted to understand her better. Chiyuki is also the person who tried to have him smile, having looked forward to it throughout the series and finally, before being sent off, sees him with a geunine smile as she heads for reincarnation, crying over being separated from him but happy with their time together. Their exact feelings for each other seem to be in a romantic notion as Nona describes their relationship as love between an arbiter and a human.

Nona
She is Decim's boss and by extension, Chiyuki's. Nona assigned her to Decim as an assistant and while the two have not interacted since episode 2, the former believes she has a somewhat good understanding of humanity but still has much to learn.

Nona sees Chiyuki, another human female that an arbiter has fallen for, as a chance to test out and show Oculus and the other arbiters that love between a human and an arbiter is acceptable on all circumstances and isn’t a violation of the law Oculus enforced.

Mother
Her mother frequently shows up in her memories and the two seemed to have a strong bond. While she had a close bond with both of her parents, her mother seems to show up far more often in her memories, possibly because her father is busy with work, and her mother was the one she regretted leaving behind the most.

Quotes

 * "I'm sorry.. for not valuing my life. I'm sorry.. for not understanding how you felt. For causing you so much grief.. I'm sorry. For not letting you have a proper goodbye.. I'm sorry."

Trivia

 * The picture book, 'Chavvot' and ice skates play a big part in Chiyuki's identity, Chavvot being an inspiration for her passion of ice skating.
 * She appears to be a decent cook, as seen in episode 7.
 * She has a closet filled with spares of the outfit she wears when assisting at Quindecim.