Nao has unkempt long, dark pink hair and eyes of the same color. She wears an orange shirt with puffed up sleeves that cut off just above the elbow and dark denim pants under a blue smock apron.
Her old high school uniform, seen when talking to Mishima in a flashback, is made up of a long-sleeved yellow shirt mostly covered by a blue blazer, a green skirt, and a red bow on the collar.
Being a participant of the Death Game, she wears a collar device.
She is initially timid and shy and primarily stays with her teacher Professor Mishima, whom she idolizes to the extent of wanting to stand in anyone's way if they say negative things about him.
She is a very emotional and clever person, immediately catching onto the fake Reko's change in personality compared to the real Reko. She also cares about her friends, as shown when talking with Gin, Reko, or Sara.
However, throughout the game, she gains immense mental strength and displays that she is no longer easily manipulated when the dolls try to obtain information from her.
Nao was born and raised by a very ordinary, middle-class family. Throughout school, she had somewhat below average grades but during high school discovered a passion and love for art, and begun to focus solely on that. She has great admiration for her high school art teacher, Kazumi Mishima, and even after graduation she has kept a deep bond with him and is also often seen going to his atelier. She doesn't appear to have many friends, but those she does have she holds very dearly and has had them for a long time. She tends to refrain from going out at night, generally staying at home even on days off.
She has little experience with sports, limited to compulsory PE. She has poor reflexes, but due to her inclination towards art, she has exceptional eyesight. She can remember a scene for a long time and is able to recognize the individual flaps of a bird's wings, and while this ability is within reason, it is still very impressive. Since much of this comes from practice, the only thing that can be called natural talent is her passionate love for art. She has a minimal desire for money.
Nao was driving home with her professor, Kazumi Mishima, when they were stopped at a checkpoint and then lost consciousness. The two of them awoke to their First Trial, where they were tied to beds and had to figure out how to escape. Mishima had a key that unlocked Nao's restraints, and from there he guided her to use the sandpaper so that the key could be whittled and fit unto Mishima's restraints. After escaping, they arrived in the Central Hall on the first floor.
Keiji Shinogi suggests that everyone introduces themselves. After the discussion, Q-taro Burgerberg reveals a box with a doll head inside, asking to find its other body parts. Nao stays with Reko Yabusame in the Central Hall looking after a fainted Kanna Kizuchi while the others leave to search the facility.
Once all the doll's parts have been collected, everyone gathers in the Pink Room and assembles the doll. A white gas fills the room and Sue Miley, the Laughing Doll appears. She explains they are going to do a practice vote and hands everyone a voting tablet. Nao votes for Mishima after he suggests they vote for each other. Mishima gains the most votes, and Miley makes his collar become incredibly hot, burning through his neck and killing him.
Nao is greatly affected by the death of Mishima, going so far as to run off with his severed head in a box in an attempt to protect him from the body collection. This experience, while initially causing immense distress to Nao, resulted in her becoming much more emotionally strong in the next chapter of the game, where she meets the AI version of Mishima.
Before the second main game begins, Nao is forcefully traded the Sacrifice card (from Sara) by Gashu Satou, who considers her a "non-candidate". If Sara, as the player, chooses to vote for her during the final vote, the votes will be tied with Sou, Kanna, and Nao will survive with Sara as the rest are executed by Safalin, leading to the first real ending. If Sara chooses to vote for either Kanna or Sou, Nao will be executed by a machine tightening and crushing her stomach.
After expiring, she is seen finishing her painting of Mishima that she mentioned when Sara found her hiding in the Kitchen. Mishima sits patiently comforting her, as well as Reko if she died during the Final Attraction.
Nao's family is described as 'extremely average'. She's an only child, and both of Nao's parents are in good health, Nao has good relationships with the both of them. Her father has been an office worker for 20 years and her mother has carried various jobs. Apparently, her father is under her mother's thumb, when they argue Nao tends to side with her father to resolve the conflict.
Nao considers Mishima as her friend and looks up to him dearly, even after graduating from high school. Before they got kidnapped, Nao stressed about her exams and the professor shared the story of him failing his college exams to try and comfort her, making Mishima some sort a mentor. She is angry toward people who view the professor as a bad guy, evident of when she snapped at Keiji when he stated he found Mishima suspicious, telling him to repent and to not judge a book by it's cover. In the manga when Keiji puts Mishima into a headlock, she proceeds to hit him in the back of the head angrily and smiles when the police officer later states that Mishima isn't as bad as he thought he was. After Mishima's death, however, Nao's anxiety gradually worsens as she is denial towards his death. She was also very protective of him after his death, yelling at Sara and Keiji due to her belief that they had come to take him away from her. However, his death also leads to Nao becoming stronger, as shown when she tells the AI version of him that she no longer wants to talk to him to overcome his death.
Nao and Reko become close friends over the period of the Death Game. When Nao went into a panic after Mishima's death and hid from the others with his head, Reko was the most worried. After Nao is freed from the kitchen, she is informed by Keiji that she should show herself to Reko since she was restless about her disappearance. Reko also stands up for Nao during the first Main Game when Q-taro questions if she, Gin, and Kanna are worthy of surviving. Nao is quick to see that Reko seemed different with her being the first one. Because of her persistence, it is possible to push the fake Reko and save the real Reko at the cost of her brother. When Alice dies, Reko tells at Sara and Nao to leave but quickly calls Nao back and sobs for her to stay by her side, to which she obliges. At the end of the second Main Game, if Reko is still alive, Nao thanks Reko for being her friend. If Alice is still alive, after Nao's execution, she is seen finishing her portrait of Mishima while he sits in front of her and Reko watches from beside Nao, proving that Nao holds Reko to a similar degree of affection as Mishima.
|Person||What they call Nao||What Nao calls them|
|Sara||Nao||ナオさん, Nao-san?||Sara||サラちゃん, Sara-chan?|
|Joe||Nao||ナオさん, Nao-san?||ジョーくん, Joe-kun?|
|Keiji||Nao||ナオちゃん, Nao-chan?||Keiji|| おまわりさん, Omawarisan?|
刑事さん, Keiji-san?, lit. "Mr. detective; Mr. police officer"
|Shin|| Miss Nao|
|ナオさん, Nao-san?||Sou||ソウさん, Sou-san?|
|Gin||Big sis Nao||ナオ姉ちゃん, Nao nee-chan?||Gin||ギンくん, Gin-kun?|
|Kanna||Nao||ナオさん, Nao-san?||Kanna||カンナちゃん, Kanna-chan?|
|Q-taro||Nao||ナオ, Nao?||Qタロウさん, Q Taro-san?|
|Reko||Nao||ナオ, Nao?||Reko||レコちゃん, Reko-chan?|
|Alice|| Nao Egokoro|
| 絵心 菜緒, Egokoro Nao?|
|Nao (self)||私, Watashi?|
|Mishima|| Miss Nao|
|ナオさん, Nao-san?|| Professor|
|先生, Sensei?, lit. "Teacher"|
|Kai||Miss Nao||ナオさん, Nao-san?||Kai||カイさん, Kai-san?|
|Person||What they call Nao||What Nao calls them|
|Ranger||Nao Egokoro||ナオ, Nao?|
エゴコロ ナオ, Egokoro Nao?
|Safalin|| Miss Nao|
| ナオさん, Nao-san?|
絵心 菜緒, Egokoro Nao?
|Gashu||Nao Egokoro||絵心 菜緒, Egokoro Nao?||フロアマスターさん, Furoamasutā-san?, lit. "Mr. Floormaster"|
- Her likes are listed as Mishima-sensei, painting, and cute things in her character profile.
- The kanji that make up her first name are 菜, na?, lit. "greens" and 緒, o?, lit. "cord, thread".
- The kanji that make up her last name are 絵, e?, lit. "picture" and 心, gokoro?, lit. "heart"
|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|