Saiko Yonebayashi

Saiko Yonebayashi (米林 才子, Yonebayashi Saiko) is a Rank 2 Ghoul Investigator, a Quinx, and a member of the Quinx Squad.

Appearance
Saiko has two thick sections of hair worn in pigtails with uneven fringed bangs, possibly as a result of her laziness. Her kakugan is located in her left eye because of her status as a Quinx, and her face appears rather youthful; Saiko is a bit heavier than the average CCG agent, with notably thick and chubby legs. She is very short, especially for her age.

Personality
Saiko dislikes having to work, as she prefers having a peaceful, happy-go-lucky and carefree life by playing video games and eating junk food excessively. She often oversleeps, which earns her the absence from most missions. While not trying to reduce it, she is apparently embarrassed about her weight, humorously covering it during her introduction.

Background
Saiko is one of two children, with a brother of unspecified age. When they were young, their mother abandoned her husband and took the children to live with her lover. The couple opened a bar together, but struggled financially. Because the tuition was cheap, Saiko and her brother were sent to CCG's Junior Academy rather than a normal school. She frequently slacked off in her classes, playing video games and getting in trouble with her teachers as a result.

As graduation approached, she had no interest in becoming an Investigator. Instead, she was among the students that took the Quinx Aptitude test and determined to be the best candidate. Her mother was offered considerable financial compensation in exchange for consenting to the surgery, pressuring Saiko to become a Quinx against her will.

Torso Investigation
While Sasaki and Mutsuki visited Cochlea to gather information on Torso, Saiko was left at home.

Nutcracker Investigation
Mutsuki and Shirazu secretly discuss plans for a "raid", after confirming that Saiko would be home at 9pm. That night, they meet with Urie and head upstairs to their teammate's room. In her room, Saiko is playing a video game when she hears her teammates approaching and attempts to hide under her covers. When she refuses to open the door, Shirazu and Urie use their kagune to break the door off its hinges.

They confront her about neglecting her duties, which she justifies by claiming Urie told her to "develop her skills" alone. To convince her to stop slacking off, Urie falsely claims that their superiors have been discussing firing her. Worried that she will be sent back to her abusive mother, Saiko promises to work hard.

In secret, Urie thinks to himself that he intentionally left Saiko out of things while Squad Leader. But now, he plots to use Saiko's laziness to destroy the team from within and discredit Shirazu as a leader.

The next morning, she oversleeps again and the team is unable to wake her up. This causes them to be late to their meeting with Juuzou Suzuya's team. Eventually, Shirazu arrives at the meeting carrying her on his back -- shocking everyone, because she is still sound asleep and in her pajamas.

The team are assigned to shadow Nutcracker and listen in on her meeting with an associate. When Shirazu is unable to make out what they are saying, he asks Saiko to listen in. She describes the sounds of a hamburger steak cooking in the kitchen, annoying him to the point he hits her over the head and begins yelling. Saiko ducks behind Mutsuki, begging him to protect her.

Observing them, Urie thinks how trying to keep track of Saiko has left Shirazu exhausted and irritable. He spends every morning in her room, banging on pots and yelling at her to attempt to make her get out of bed. Even so, she rarely wakes up before the afternoon. This stress causes Shirazu to knock over a glass and draw attention to their group, spoiling the mission.

Later, Shirazu and Mutsuki wonder why Sasaki hasn't taken any action to make Saiko do her job.

During one of the meetings between the two squads, Saiko begins dozing off. She is lectured by first Shirazu, and later Sasaki, for her behavior.

For the undercover operation, she is tasked with dressing up Shirazu and Mutsuki as women. She compliments Mutsuki on his features, but teases Shirazu over his appearance. Saiko spends most of the time at the nightclub dancing, but warns Sasaki when Mutsuki ends up getting drunk.

As Sasaki worries about the upcoming operation, Saiko approaches him and asks him to clean her ears.

Saiko continues to slack off during training, pretending to be dead rather than join in sparring with the team's mentor. She complains about the harsh exercise, stating that she's going to lose weight.

She next appears at The Chateau with Shirazu, scrounging for something to eat. When Shirazu suggests more training, she begins to tease him since the word sounds similar to the name "Keiko" -- suggesting he has a girlfriend. Their argument is interrupted by a visit from Hanbee Abara, who invites them out to lunch. Saiko talks about her progress in Kerbal Space Program. Afterwards, Abara asks them to accompany him to the hospital, where he introduces them to a comatose Yukinori Shinohara.

As the pair leave the hospital, they encounter Touka Kirishima. Noticing Shirazu's blush, she begins to tease him again.

Auction Raid
Saiko reluctantly participates in the Auction Raid, stating that she would like to flee immediately and noting her battle power wouldn't be of much help to the team. She silently wishes for Mutsuki to stay safe. During the initial charge, Saiko lags behind the other investigators, avoiding combat.

She stands back while Urie, Shirazu, and Sasaki fight Kanae. She expresses relief when Mutsuki is safely retrieved. She along with Sasaki and Shirazu head on to exterminate Nutcracker.

As the squad heads towards Nutcracker's location, they are attacked by Takizawa. Sasaki orders his squad to retreat and asks Shirazu to take care of Saiko. Saiko and Shirazu along with Naoto Hayashimura locate Nutcracker in the administrative building. Shirazu discovers the trick behind Nutcracker's detached kagune and he forms a plan with Hayashimura and Saiko. After Nutcracker is impaled by her own trap, Saiko activates her kakugan. She is then seen exhausted and panting while Nutcracker lies incapacitated with her left arm torn off. Hayashimura seems shaken having seen Saiko fight, and thinks to himself he's not sure who the monster is anymore.

After Nutcracker's defeat, she hears Sasaki's wails of pain as they're blared through the intercom. She turns on the monitors and is horrified by what she sees.

She later arrives at the Administrative Building where Sasaki has been left nearly incapacitated Takizawa, but afraid, she remains hiding. She's shocked when she sees Sasaki suddenly saved at the last minute by Hinami. During their fight, Saiko continues to remain hiding until Sasaki steps in to fight for Hinami, intending to let go of his identity and allow Centipede to take over. She calls out in tears for her "maman" to not go, which convinces Haise to fight with his own strength instead of giving in.

She watches as Sasaki and Takizawa duke it out until they come to a draw. When Arima arrives and is stopped from killing Hinami by Sasaki, she's nervous about what might happen.

Post Auction
A month has passed since the Auction mopping-up operation and Saiko is helping Sasaki prepare for a Christmas party. She sings while decorating the Christmas tree. That night at the party, she has fun with the others, eating and playing video games. She receives a new video game as a gift from Sasaki.

Rosewald Investigation
Spring has arrived and the CCG is holding their awards ceremony where Saiko is promoted from Rank 3 to Rank 2. She enjoys herself at the after party, stuffing her face with all sorts of food.

When the Quinx squad was lured into a trap in an empty parking garage by Kanae and hired Aogiri hitmen, Saiko and Mutsuki are instructed by Sasaki to go aid Urie and Shirazu when two white suits from Aogiri showed up. After encountering Torso midway, Mutsuki fends the ghoul off and tells Saiko to go in hiding, which she complies. After a while, a strange looking ghoul appears in front of Saiko. That ghoul, a member of Aogiri, corners her. The ghoul, while holding her down, starts munching on her right forearm as Saiko writhes in agony. Suddenly, a robed figure arrives and fends off her attacker by using, what seemed to be, a high-speed attack and vanishes as the inverstigator's comrades arrive at the scene, while she dazedly murmurs out a thanks.

Haise Sasaki
Sasaki has great sympathy for her situation, and admits to being too soft on her. Saiko has a very close relationship with him, referring to him affectionately as "Maman" and treating him as a parental figure. She loves his cooking, and cuddles with him at several points showing that the two have a strong familial bond.

Ginshi Shirazu
Shirazu considers her laziness a constant frustration, and their relationship is strained by his efforts to force her to take her job seriously. She frequently gets berated by him, but they still seem to get along outside of their work. During Shirazu's fight with Nutcracker after he avoided getting smashed by the ghoul Saiko (probably) jokes with him, asking if his jewels were intact-which he responded that they fortunately were.

Tooru Mutsuki
Mutsuki is often stuck serving as a peacekeeper between Shirazu and Saiko. When Shirazu berates her, she looks to Mutsuki for protection. She appears to care for him, wishing for his safety during the Auction and expressing relief when he is retrieved.

Kuki Urie
He describes her as an ill-fitting cog in the machine, and intentionally kept her from working with the team while Squad Leader. However, once he loses his position, he considers her an ideal tool to use against Shirazu. He manipulates and lies to her, considering her stupid for not seeing through his bluff.

Powers and Abilities
She appears to have very acute hearing ability. As she refuses to work, nothing is known about her overall abilities. She appears to have low stamina, most likely due to the fact she rarely trains. However, she is noted to have the highest aptitude with the Quinx operation by far.
 * Bokusatsu No. 2: Saiko possesses a koukaku quinque that is shaped like a hammer.
 * Rinkaku Kagune:  Saiko's kagune was initially portrayed as two tentacles resembling a reptilian's tail. What she utilizes during the Rosewald Investigation however it appears to be a bulky structure with additional tentacles protruding from its end, being easily several times bigger than Saiko herself. It appears strong enough to take huge gouges out the ceilings and floor and capable of severing a ghoul of Noro's stature in a single blow. It also appears to take a significant amount of stamina to use, as Saiko is always seen panting on the floor after a single usage.

Trivia

 * Saiko has a RC level of 850, which is the third highest compared to the other members of Quinx Squad.
 * Shirazu states she had the lowest grades out of their group at the Academy.
 * Her comrades refer to her as a NEET in Chapter 8. The term is used for young adults that are "Not in Education, Employment, or Training".
 * According to an omake in Volume 1, Saiko is a typical "otaku" with an interest in anime, manga, and video games. She has a twitter Mutsuki uses to spy on her.
 * Due to her interests, Saiko references numerous other series. In her room, a poster for the series Himouto! Umaru-chan can be seen, and while talking in her sleep she makes reference to the online game Final Fantasy XI.
 * In Tokyo Ghoul Trump, she is featured as the "Three of Hearts".
 * Her kagune strongly resembles a caterpillar infected with Ophiocordyceps sinensis.