|Japanese Name||三葉 琴音|
|Relatives||Kazene Mitsuba (Mother)|
Kiyone Mitsuba (Older sister) †
|Novel Debut||Void: Chapter 3|
Mitsuba is an idol singer, and draws the attention of Shuu Tsukiyama and Chie Hori. Her real name is Kotone Mitsuba (三葉 琴音, Mitsuba Kotone) though she uses her surname as her stage name while working professionally.
Mitsuba is an extremely beautiful young woman, with auburn hair and green eyes. She wears the sort of clothing typical of an Idol, with decorative ribbons and frills. When not working, she tends to favor casual clothing that allows her to go unnoticed.
Mitsuba has a very soft-spoken and serious nature, exactly the opposite of what an Idol is supposed to be. She is very unassertive, and easily led along by others. Haunted by the loss of her family, she is attempting to live her sister's dream of being an Idol, but carries a heavy emotional weight.
Mitsuba attends a festival in Tokyo, where Chie Hori first takes several photographs of her and becomes interested in taking a portrait of her. While meeting with his human friend, Tsukiyama sees the photographs that Chie had taken and becomes fascinated with Mitsuba. He declares his intention to eat her, leading to the pair competing over who will get to her first.
Chie uses her resources to locate Mitsuba's home address, and approaches her boldly at her apartment. While Mitsuba protests in confusion, Chie sprays cheap perfume everywhere and then drags her away from the building. Outside, they watch Tsukiyama break in and immediately flee upon discovering the overwhelming scent in the apartment. Mitsuba is informed she is being targeted by a Ghoul, and Chie advises her to hide somewhere until she can take care of things. When she asks about contacting CCG, Chie advises against it and warns her about the influence of the Tsukiyama family. Accepting this, Mitsuba and Chie begin staying at a house in the 23rd Ward for safety.
While there, Chie inquires about Mitsuba's past and learns the reason she became an idol. Her older sister dreamed of being an idol, but as she grew older, their mother began to fight with her over it. One day, her sister and mother fought violently over it, leading her sister to run away. Mitsuba's parents fought over their elder daughter's disappearance, and a year later her mother vanished as well. Eventually, her father remarried and move over seas, leaving Mistuba alone. She decided to become an idol, hoping her fame would reunite her with her missing family.
Chie agreed to help her find her missing family, and called Ikuma Momochi to help them out. Their investigation leads to the recent news story about Yuujirou Utsumi and his adopted daugher, a Ghoul that helped him prey on young women. Their housekeeper, an old woman named Otokaze, had stabbed her employer at the hospital before trying to commit suicide. Chie informs Mitsuba that Otokaze is her mother, and was most likely searching for her missing daughter by working for the Utsumi household.
Mitsuba asks to go to the hospital, but as they leave, the group is ambushed by Tsukiyama. They are forced to jump out a window to escape, with Ikuma revealing himself as a Ghoul to save the girls. He tries to fight Tsukiyama alone, but is easily defeated. Mitsuba is cornered by Tsukiyama, but Chie interrupts them and explains that she has been exchanging emails with someone and shows him the name of her contact — Ken Kaneki.
He arrives to meet with Chie as she'd planned, and speaks briefly with her about things. Out-witted, Tsukiyama is forced to give up on pursuing Mitsuba and even accepts the order to escort her safely to the hospital. There, she is reunited with her mother and learns that her sister was among the Utsumi's many victims. However, her mother's memory has degraded to the point she mistakes Mitsuba for her sister — but to ease her mother's guilt, she pretends to be Kiyone and states she has achieved her dream of being an idol. Afterwards, she resolves to begin using her sister's name — Chie snaps a portrait of her determined face, getting the photo she'd been hoping for.