Kozakura

Kozakura is very short and looks much younger than her real age—Sorawo Kamikoshi even mistook her for a grade schooler at first meeting.

She has a child-like face and body, but her age is at least in her late twenties.

When she goes out to restaurants, she always shows her ID to prove she's not underage.

She rarely leaves her house and prefers to buy things online.

Her favorite drink is hot cola, which she likes to heat in the microwave and drinks from a mug with Tove Jansson's art.

Kozakura prefers not to appear too childish and hates it when people point out her small frame.

Kozakura is blunt and straightforward, with a sharp tongue and little patience for nonsense.

Even though she acts grumpy, she's actually quite caring about her friends, but she does not show it easily.

She is very cautious and easily scared, which makes her reluctant to enter the Otherside herself.

Kozakura prefers being alone and finds too much social interaction tiring, though she can be friendly when needed.

Her quick thinking helps her in tough situations, but she can burn out fast and needs sugar to keep her energy levels up.

She often drinks cola to stay energized, especially when working.

She reacts angrily if people make fun of her size or compare her to a child.

Kozakura lives in a large house near Shakujii Park, surrounded by high brick walls and covered in ivy.

She is a researcher specializing in cognitive science, trying to find a scientific explanation for the events and monsters of the Otherside.

Her last name is Kozakura, but her first name is not known in any of the novels up to volume 9.

She was friends with Satsuki Uruma in college and joined the DS Research Foundation (DS Ken) to support Satsuki’s research, though she was against the risky Otherside exploration.

Even now, the DS Research Foundation supports her research by buying the items that Sorawo and Toriko find on their expeditions.

She attended an all-girls school and later went to graduate school.

Her birthday is November 11.

She dislikes low-carb snacks and loves hot cola.

When in bad moods, she shouts things like "I'll kill you!" especially when teased about her height.

Kozakura is skilled in cognitive science and uses her knowledge to understand the Otherside and its strange phenomena.

She is tech-savvy, setting up complex equipment at home, and is working on a software project called "Kaidan Craft."

This software can generate and analyze ghost stories to study how the Otherside communicates through them.

Eventually, she aims to make a language model that can communicate with the Otherside itself.

Kozakura is also a good driver and has a driver’s license.

She once owned a car but gave it up because she found driving alone boring.

• Satsuki Uruma: Former college friend; Kozakura is angry and upset about Satsuki's disappearance into the Otherside and wishes she could have stopped her.
• Sorawo Kamikoshi and Toriko Nishina: Kozakura buys Otherside objects from them and acts as a consultant and advisor. She worries for their safety and discourages them from risking their daily lives.
• Mitake and Tsuji: Friends from the DS Research Foundation.
• Kasumi: After Sorawo finds Kasumi in the Otherside, Kozakura becomes her guardian.

• Kozakura streams online as VTuber "Yozakura," using an avatar based on Satsuki.
• She created an earlier avatar based on her own appearance but dropped it because she attracted unwanted fans.
• Her favorite way to relax is streaming and chatting online.
• She is not a fan of low-carb snacks and enjoys delivery pizza.
• Most of her meals are takeout, and she rarely cooks for herself.
• The big dining table in her home is rarely used, but she keeps it just in case she has guests.
• She keeps a Remington M870 shotgun hidden under the house for self-defense.
• She likes collecting odd souvenirs, such as raccoon figurines, which she uses to "control fear" by giving scary things a name and reason.

• "Stop it. If you stop caring about this side, you really won’t be able to come back from the Otherside."
• "When things get dangerous, what keeps you alive is wanting to come back to your normal life. If you give up on your daily world, both of you will vanish for good."
• "I wish I could be your anchor, but I know I can't. At least, don't neglect your normal life."
• "I'll kill you!"
• "Are you trying to come between me and Ponpoko?!"

The Advisor to Explorers

Kozakura is introduced as an acquaintance of Satsuki Uruma and acts as the main buyer of strange artifacts discovered by Sorawo Kamikoshi and Toriko Nishina on their Otherside explorations.

She is concerned about their safety and repeatedly warns them not to get too involved with the Otherside.

Kozakura is frustrated with Satsuki for ignoring her warnings and is angry when Satsuki goes missing in the Otherside.

Life at Home

She lives alone in a big house near Shakujii Park, surrounded by high walls and covered with green ivy.

Her workspace is cluttered with books and gadgets, and she often drinks hot cola while working at her six-monitor station.

Her dining area is large but usually empty except when guests come, like Sorawo or Toriko.

Getting Pulled into the Otherside

Kozakura is sometimes drawn into dangerous situations, such as when doors to the Otherside open in her house or when she is targeted by cultists and Otherside creatures.

Despite being scared, she faces these events with her quick thinking and scientific mindset.

VTuber "Yozakura"

Kozakura enjoys streaming as "Yozakura," a popular VTuber with an avatar based on Satsuki.

Her fans love her straightforward talking and mature "big sister" personality.

She accidentally gained internet fame as "the woman who drinks cola with her chest” after a funny streaming mishap with her avatar.

The Kaidan Craft Project

Using her cognitive science skills, Kozakura develops a program to generate ghost stories automatically, trying to "spam" the Otherside with meaningless stories to weaken its power.

The project evolves into a system for mapping and understanding language patterns in the Otherside, with the goal to one day communicate with it.

New Family

Later, Kozakura becomes the guardian of Kasumi, a girl brought back from the Otherside, and tries to understand her mysterious behavior using her scientific knowledge.

She helps Kasumi adjust to the real world, even when things get chaotic.

Connection to UFO Research

Kozakura originally became interested in the unexplained through UFO stories, not because she believes in aliens, but because she is curious about why humans see strange things in the sky and how cultural backgrounds affect people's beliefs.

Kozakura keeps her house secure with modern locks, cameras, and motion-activated lights, but sometimes her home is still invaded by supernatural events.

Her house becomes one of the main access points to the Otherside, which she doesn't like but puts up with for the sake of her friends.

She is not overly social but will go out when needed, and she even joins Sorawo and Toriko on trips, such as to a hot spring or a girls' night at a hotel, though she finds it awkward due to her small size.

Kozakura combines tough love with sharp scientific curiosity, making her a fan favorite for her wit, honesty, and the secret kindness she tries to hide.