Mishima has disheveled gray hair and light brown eyes hidden behind his circular spectacles. He wears a brown suit with a lime-colored undershirt worn with a tie, alternating between green and orange stripes.
He wears a collar as do all participants, dummies, and floor masters. Like all of the participants, Mishima wears one that was especially made for human usage.
Being a little odd, Mishima often puffs mad scientist laughs after sentences, and his emotions often conflict with his appearance. Mishima seems to enjoy acting strangely to amuse others, behaving cryptic and overly analytical of everyone's actions. His unusual social quirks aside, Mishima makes it clear he has no ill intentions and frequently reminds others to be safe and cautious. Despite appearances, Mishima is an incredibly kind, caring, and encouraging person. After his A.I. self learned about how much suffering Nao was going through after his death, he could only blame himself for it. He deeply regrets not being able to live longer, because he truly just wanted to protect Nao. He also regrets not being able to live on to see Nao continue to grow, as well as his other students.
He's shown to not only be caring towards Nao though, but he also shows great concern for Kanna and even helps to spur her onward towards hope, albeit by lying about the circumstances of the first trial.
His A.I. self mentions only two major points in his life; these being the day he became a teacher and Nao Egokoro's graduation. Even after Nao's graduation, she still visits his atelier to learn more about art from him. He greatly cares for Nao and their bond is incredibly strong.
The Death Game
On the day of his kidnapping, Mishima was teaching his students oil painting. At the end of his lesson, he drove each of his students home. When it was just Nao left to be dropped off, they were stopped at a security checkpoint and lost consciousness.
The two them then awoke to their First Trial. Like Sara and Kanna's First Trials, Mishima and Nao were tied to beds and had to figure out how to escape within 5 minutes. The key given unlocked Nao's restraints first, and Mishima instructed her to use sandpaper to whittle the key so his restraints could be unlocked as well.
Soon, he would meet the other surviving participants in the Central Hall on the first floor. Keiji suggests that everyone introduces themselves. At the end of the discussion, Q-taro reveals the box he carried through his First Trial. Inside is a doll head instructing the group to find its other body parts. Everyone splits up to search. Mishima searches the bar with Gin.
Later, Sara finds and shows a cigar, a cigar cutter, and a lighter to Mishima. He asks to hold on to the items, which Sara suspects is because he wants to smoke. He investigates the cigar by cutting it and finds a 1000-yen bill inside, which he gives to Sara along with the lighter.
Sometime after, Kanna asks Sara if she could have saved her sister during her First Trial. Mishima interrupts, and lies, saying they only had one key, and that Sara and Nao only survived because Joe and Mishima were strong enough to rip their restraints off. He then asks Sara and Joe to take the role of Kanna's older sister and younger brother.
Eventually, all the doll's limbs are collected and the participants meet in the Pink Room. The doll is assembled, and Sue Miley appears. Miley explains they are going to a practice majority vote, to prepare for the Main Game. Mishima quietly confers with Nao, requesting that they vote for each other, as an act of trust. It is later revealed that Mishima voted for himself instead to protect Nao from any harm.
Regardless of who Sara votes for, Mishima receives the most votes. Miley taunts him by saying his collar won't explode, instead, making it become so hot so that it burns through his neck, and he dies.
Miley leaves, and it is discovered that had the votes been a tie, no one would have died. Nao and Gin mourn over Mishima's body. After a while, a body collection announcement is broadcasted while a white gas fills the room. Nao panics puts Mishima's head into Q-taro's box and runs away.
On the third floor, the surviving participants find the Monitor Room, which hosts 9 monitors. After investigating one which was making a faint sound, a picture of Mishima appears on it. It is realized that it is an Artificial Intelligence of Kazumi Mishima.
Nao, bewildered by the fact that it looks and sounds just like the professor, is glued to the screen and won't move. At the end of the first morning, however, she realizes she must go and can't stay with the professor forever. She leaves, and Sara can then ask the Mishima AI what it knows about the Death Game, the kidnappers, Nao, its own memories, and the real Mishima. If Sara asks about the real Mishima, the AI will begin to make a request, but then dismiss it, saying it's nothing.
Sometime before the Final Attraction, Reko visits the Mishima AI, who makes a request of her. Keiji and Nao witness Reko breaking the AI's screen.
After the Final Attraction, Sara and Keiji explore the first floor and discover how to view the security cameras in the Monitor Room. They see that Nao's bedroom has a monitor, which the Mishima AI appears on! Nao returns to her room and they exchange a suspicious conversation.
Later, Nao performs a trick to steal Kai's laptop. She is chased to her bedroom. Under the appearance that Nao was following the orders of the Mishima AI, she connects the laptop to the monitor and the AI reveals that he isn't working with them, but rather, against them. The AI thinks it is now able to erase all the data on the laptop, but it is unable to, due to a hacking program Kai had put on it. Nao and Sou are relieved that their plan worked, and the evil AI vanishes.
Nao and Mishima get along very well with Nao looking up to Mishima greatly. On the night of the kidnapping, Nao, along with other students, were taught oil painting by Mishima and were later driven home by him. When told that he looks suspicious by Keiji, Nao is infuriated and demands that he apologizes, claiming that the professor is a wonderful person and that he shouldn't judge a book by its cover. During the second trial, Mishima asks for Nao to vote for him, telling her that in exchange, he'd vote for her. In actuality, it was to gain Nao's vote with Mishima never intending to vote for her in the first place, not wanting to put Nao in any harm's way, even if the situation didn't seem dangerous. However, because of this, Mishima earned the most votes as he, Nao, and an implied Sou voted for him, and dies. Nao is thrown into a fit of bewilderment and stays by his body the entire time. When a body collection announcement is broadcasted and the room fills with white gas, Nao is thrown into disarray, yelling that the professor isn't dead, shoving his head into the box Q-taro brought and running to the kitchen. In the dark, she questioned him over and over but was answered with silence. Nao notes how, despite however busy he was, Mishima always answered her questions with a smile. After some encouragement from Sara, Nao promises to finish her newest project, a portrait of the professor. On the third floor, after finding a Mishima AI, she is seen talking to it the entire rest of the first day, telling him about all that has happened. In her room, she yells at the evil Mishima for believing their connection to be so flimsy that she wouldn't have noticed his change in behavior. When everyone thought they could escape, Nao mentions again how she will finally be able to finish his portrait. After Nao dies, a scene of Nao painting is shown with Mishima sitting in front of her canvas while she paints his portrait, having all the time in the world to finish it.
Gin and Mishima did not have a very close relationship when introduced, as stated by Gin who refers to him as overly suspicious and is caught off-guard when learning of his occupation. The two then decide to search the bar together. Gin is frightened and heartbroken after witnessing Mishima's untimely demise, he and Nao staying behind next to the body. It is implied that he views Hayasaka similarly to how he viewed Mishima.
|Person||What they call Mishima||What Mishima calls them|
|Sara||Professor Mishima||ミシマ先生, Mishima-sensei?||Miss Sara||サラさん, Sara-san?|
|Joe||Mishima||ミシマ先生, Mishima-sensei?||Joe||ジョーくん, Joe-kun?|
|Keiji||Mishima||ミシマさん, Mishima-san?||Keiji||ケイジさん, Keiji-san?|
|Shin||Mishima||ミシマさん, Mishima-san?||Sou||ソウさん, Sou-san?|
|Gin||Old guy||おっさん, Ossan?, lit. "Old man; uncle"||Gin||ギンくん, Gin-kun?|
| ミシマさん, Mishima-san?|
|Miss Kanna||カンナさん, Kanna-san?|
|Q-taro|| Old man|
| おっさん, Ossan?, lit. "Old guy; uncle"|
|Reko|| Nutty professor|
| ヘンテコ教師, Henteko kyōshi?, lit. "Weirdo teacher"|
|Alice||Mishima||ミシマ, Mishima?||Gonbee||ゴンベエさん, Gonbē-san?|
|Nao||Professor||先生, Sensei?, lit. "Teacher"||Miss Nao||ナオさん, Nao-san?|
|Mishima (self)||私, Watashi?|
|Kai||Kai||カイさん, Kai-san?|| Kazumi Mishima|
| ミシマカズミ, Mishima Kazumi?|
|Person||What they call Mishima||What Mishima calls them|
|Miley||N/A||N/A||Miss Miley||ホエミーさん, Hoemī-san?|
|Ranger|| Kazumi Mishima|
| 三島 和己, Mishima Kazumi?|
ミシマ カズミ, Mishima Kazumi?
|Safalin||Mishima AI||ミシマ(のAI), Mishima (no AI)?||Miss Safalin||ハンナキーさん, Han'nakī-san?|
- His likes are listed as painting, his students, and tea in his character profile.
- The kanji that make up his first name are 和, kazu?, lit. "peace" and 己, mi?, lit. "oneself".
- The kanji that make up his last name are 三, mi?, lit. "three" and 島, shima?, lit. "island".
- He had a 3% chance of winning the Death Game.
- While naming Midori in Chapter 3, Part 1, Mishima is one of the only survivors of the First Trial that does not generate a reaction from him, the other being Shin.
|Participants||Sara Chidouin • Joe Tazuna • Keiji Shinogi • Shin Tsukimi • Kanna Kizuchi • Gin Ibushi • Q-taro Burgerberg • Reko Yabusame • Alice Yabusame • Kazumi Mishima • Nao Egokoro • Kai Satou|
|First Trial victims||Dummies||Hinako Mishuku • Naomichi Kurumada • Shunsuke Hayasaka • Anzu Kinashi • Mai Tsurugi • Ranmaru Kageyama|
|Kugie Kizuchi • Megumi Sasahara|
|ASU-NARO||Floor Masters||Sue Miley • Rio Ranger • Tia Safalin • Gashu Satou • Sou Hiyori|
|Meister • Man from the Memorandum • Maple|
|Other||Mr. Chidouin • Mrs. Chidouin • Ryoko Hirose • Botsun • Girl from the Memorandum • Mr. Policeman • Kuro|
|Survival Island characters||Rei • Jin Mutou • Touko Rikuno|