Quin

Quin (クイーン Kuin) is a worker in the information processing bureau, and is in charge of sending the “memories of the dead” to arbiters, as well as testing their abilities. She used to be an arbiter in Quindecim until Decim replaced her.

Appearance
Quin is a tall woman with pale-colored skin. She has short dark brown hair and fringes almost covering her forehead. One of her light green eyes is covered with a yellow eye patch strapped in a brown band. This eye patch holds a lens that she uses to study a memory.

She wears a lab coat atop a gray hoodie and long pale blue skirt. She dons a pair of beige flat shoes and puts her pin on the left side of her lab coat's collar.

Personality
A chatterbox who loves drinking sake and gets along very well with Nona. She is very enthusiastic about all alcohol in general, but especially more so if it comes from the world of the living. She seems to regret taking a position in the information processing bureau, as she states that the work done in that department is endless and fast-paced.

Plot
Quin is first prompted by Nona in Episode 2 to send the memories of Decim's oncoming guests. She sent the memories and replied via telepathy. Quin herself did not make an appearance in this episode.

In Episode 5, Quin is mentioned by Nona when explaining to Decim that he was due for Quin's Memory Test and that he had failed to handle the situation properly, as his attention was diverted to a decoy.

Quin finally makes her first full appearance in Episode 7 arriving at Nona Ginta to have a few drinks with Nona. Over the course of the episode, Decim explains Quin's backstory to the Black-Haired Woman in a flashback. In the flashback, Quin is excited to meet Decim and frantic to hand over the position to him, along with all of the bar's alcohol. While Quin makes her final judgement as an arbiter on two guests, Nona tests Decim and Ginti in a separate room where they view their game and use the judgement devices where they deem it to be necessary. After Quin's final guests take their leave, the four celebrate and Quin is amazed by Decim's martini-making skills. Quin is also shocked to learn of Decim's respect for humans, though she and Nona take it as a positive omen. As Quin parts Quindecim for the last time, she leaves Decim with advice to find something that he treasures.

Later in the episode, Nona notices that Quin is less upbeat lately and asks her about it. Quin responds by complaining about the hard labour in the information bureau, and notes that people are dying far too quickly. After, she asks Nona about her work in management, and when she replies negatively, she advises her to make sure that Oculus doesn't find out about Decim's implanted human emotions. She also asks Nona why she spends so much time focusing on Decim, but passes out before hearing the answer.

Quin appears again in Episode 10 alongside Clavis counseling Nona after her concern with Decim's doubts about judgement. Nona requests that she sends all of Chiyuki's memories to Decim and have them recompiled. Quin is baffled, but agrees to do so, and for her trouble, Nona offers her a bottle of whiskey from the living world, much to her excitement.

Quin briefly appears in the beginning of Episode 11, tired after compiling Chiyuki's memories. She and Nona come to the conclusion that though her memories may be appear beautiful at first glance, there is nothing in life that is as it seems.

Episode 12 marks Quin's final appearance, where she and Castra have gathered for brunch with Nona on the 90th floor. She and Castra ask Nona what they should do now that Oculus is aware of Decim's emotions, and she assures them to let it be.

Quin's fate remains unknown, but it's likely she returned to her work as normal in the bureau following the events of Season 1.

Nona
Quin seems to like Nona's company, and appreciated it when Nona brought her wine from the world of the living. They are shown to have a fairly close relationship as Quin did not hesitate to tell Nona about her regrets or help Nona find a specific set of memories among the endless piles stored in the information bureau. The two seem to get along as good friends.

Castra
Quin is shown to be acquainted and on good terms with Castra, as the two are regularly in contact with Nona.

Decim
Quin was initially overall impressed with Decim's ability on handling her former bar and gives him high praise for the work he does. She sees Decim as her proud successor.

Trivia

 * Quin seems to be able to effectively switch her attitude when in front of her guests in Quindecim, as she appeared solemn before them in Episode 7.
 * Quin was probably influenced to switch over to the information-processing bureau because the alcohol is provided for the workers there.
 * Quin is the only known arbiter to be exempted of the first of the four rules of arbiters; "Arbiters cannot stop making judgements, for it is more than their career, it is why they exist." Quin was an arbiter that eventually ceased making judgements to work in the information-processing bureau.