Saiko Yonebayashi

Saiko Yonebayashi (米林 才子, Yonebayashi Saiko) is a Rank 3 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's true weight is unknown but is believed to be dangerous for her occupation, and she is rather chubby, with notably thick and chubby legs, she also appears to have big breasts. 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.

She is excessively lazy to the point of being a hikikomori, unable to remove herself from her room without the intervention and often force of others, even jeopardizing her occupation. Saiko is also depicted as greedy, and heavily involved in her videogames to the point of escapism.

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 offering considerable financial compensation in exchange for consenting to the surgery, forcing 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. Recently, Dr. Shiba noted that Saiko had been gaining too much weight due to staying away from missions, and instead eating excessively and oversleeping.

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 lose her comfortable life and be forced to go back to working at her mother's bar, 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 exploits in a video game, and devours a large amount of food. 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.

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 substitute. 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.

Tooru Mutsuki
Mutsuki is often stuck serving as a peacekeeper between Shirazu and Saiko. When Shirazu berates her, she looks to Mutsuki for protection.

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 is noted to have the highest aptitude with the Quinx operation by far.
 * Rinkaku Kagune:

Trivia

 * Saiko has a RC level of 850, which is the fourth 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 attending school, unemployed, not seeking work or training, and uninvolved in contributing to the household through chores.
 * According to an omake in Volume 1, Saiko is a typical Otaku with interest in anime, manga, video games, and has a twitter Mutsuki uses to spy on her.
 * She seems to play Kerbal Space Program, an indie spaceship simulator videogame.
 * 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.