Hosho Osato (大郷宝生, Ōsato Hōshō) is the head of the Osato family. He and his wife doted on their daughter Naoko, to the point they refused to let her live alone in S-City and would rather have her go to school by private car. He settled on Shuichi as a suitable spouse for her and brought Shuichi to meet Osato one day, unaware that she just murdered the gardener, Gunpei Kamafusa. Noticing that Naoko is in the guest house, he knocks at the door and almost opens the door with a spare key, but when Naoko says she's changing clothes, Mr. Osato prefers to leave.
Shuichi (修一, Shūichi) is the fiancé of Naoko Osato, set to be married after her graduation. The marriage was arranged by their respective families. One day, Shuichi comes to visit Naoko at her home and suspects she was with another guy. She was actually with her secret boyfriend Gunpei Kamafusa but just murdered him a few moments earlier in an accident. She manages to hide his corpse before Shuichi sees her in the kitchen and he apologizes for getting the wrong idea.
After their marriage, he seems to care about her, but she continues to love Gunpei even as a corpse. Their life together was happy, and even though they didn't burn with passion for each other, they were blessed with two kids (actually Gunpei's children, but Shuichi didn't know this).
Kiriko Osato (大郷桐子, Ōsato Kiriko) is the daughter of Naoko Osato. She surprised Rohan Kishibe in the woods investigating her house and runs away. Rohan tries to grab her but accidentally makes her trip, nearly killing her. It is revealed that she is possessed by the Mutsu-kabe Hill Yokai but Rohan wards it off by making the girl unable to notice Rohan's presence. She peacefully returns to her mother afterward.
Kai Osato (大郷櫂 , Ōsato Kai) is the son of Naoko Osato. He wears a shirt with "SBR" on it, and declares that he will become a gardener when he grows up, both alluding to his real father being Gunpei Kamafusa.
The Gods of the Mountain (山の神, Yama no Kami) are the entities that put the Village of Millionaires under a curse. The residents (or those who want to be one of them) of the village who show good manners gain something, usually money, while those who don't lose things, mostly the life of a friend. The village had 11 residents, all at the age of 25, that became rich from one day to another after living in there. Kyoka Izumi, who wanted to buy a house in there, went to the village with Rohan Kishibe and was greeted by the gods' butler, Ikkyu. Izumi failed at her test and lost the lives of her mother and fiancee. The gods can give as many chances as they want, but one by one things will be lost if the person keeps failing. After realizing the identity of Ikkyu's master to be the Gods of the Mountain through Heaven's Door, Rohan decides to leave the place with Izumi and never go back. Later, in 'Thus Spoke Kishibe Rohan Episode 11: Drip Painting Style, Rohan wonders whether the gas-powered car he uses to stop the eco-terrorist is a gift from the gods.
Virgina (ヴェルジーナ, Verujīna) is Tonio Trussardi's girlfriend who lives in his hometown, Amalfi, Italy. She has a large brain tumor that even Pearl Jam couldn't heal and could no longer walk or stand. Rohan discovers that Tonio brought her to Morioh in hopes of Morioh's disk abalone cooked together with Pearl Jam having a possibility of healing her.
Some time after Rohan successfully poaches some abalone, he is glad to see Virgina together with Tonio in the kitchen, with her no longer in a wheelchair.
Frida Giannini (フリーダ・ジャンニーニ, Furīda Jannīni) is the creative director of the Gucci brand. Gucci's philosophy is revering tradition, seeking the greatest quality, and innovating. An artisan describes how Giannini is the pinnacle of the brand, as she has respect for all of the iconic products Gucci designed throughout the years. Moreover, they were able to create new revolutionary designs through her talent. Gucci's artisans are considered Giannini's right-hand men because they give life to her designs by making them into physical objects. The brand's trusted reputation all over the world is thanks to the techniques handed down to the artisans over many generations combined with Giannini's designs.
Noboru Mochizuki (望月 昇, Mochizuki Noboru),[Note 1] aged 50, is the husband of Haruko and the father of Aki and Takeru. He is an office worker and the current head of the Mochizuki family. He values the family tradition of viewing the moon on the day of the Harvest Moon since he is passionate and protective of his family. Due to how relatives who didn't view the moon on that day had their lives cut short, including his father and his younger brother, who died when Noboru was 22. In contrast, he also knows of his grandparents and ancestors who lived long lives due to understanding the importance of viewing the moon as a family. He keeps this same belief firmly to stop anyone else from dying. For this reason, he forcibly cancels any plans the family may have had to watch the moon together in their backyard.
Haruko Mochizuki (望月 晴瑠子, Mochizuki Haruko),[Note 1] aged 46, is the wife of Noboru Mochizuki and mother of Aki and Takeru. She is a full-time housewife, and it's revealed that she has cervical cancer, as shown by a positive test result she had received. Noboru reassures her that if she lives past midnight on their moon viewing, her medical treatment will go well, and her health is guaranteed to recover.
Takeru Mochizuki (望月 猛, Mochizuki Takeru),[Note 1] aged 15, is the son of Noboru Mochizuki and younger brother of Aki. He is a middle school student and baseball club member who plans to attend college with a baseball scholarship. He has an important baseball game on the day of the Harvest Moon, but his father forbids him from attending to stay for the moon viewing. Once the moon viewing started, he showed a complete turnaround and enjoyed himself while playing with a toy helicopter. He also saved his grandmother from choking when he accidentally hit her with his toy helicopter.
Mitsu Mochizuki (望月 ミツ, Mochizuki Mitsu),[Note 1] aged 78, is the wife of Sakuzo Mochizuki and mother of Noboru, Mamoru, and Akiko. She is also the grandmother of Aki and Takeru. As the family goes out to the backyard during the Harvest Moon, a chain reaction of events causes a goldfish to be flung into Mitsu's mouth, almost choking her to death. However, Takeru's toy helicopter lands on her throat, making her spit it out. She places the fish back in its bowl afterwards.
Mamoru Mochizuki (望月 護, Mochizuki Mamoru)[Note 1] is the second son of Sakuzo Mochizuki. He is the brother to Akiko and Noboru and the uncle of Aki and Takeru. 28 years prior to the story, when he was coming home from school during the afternoon at 17, he saw one of the neighbors' kids were drowning in a river. He tried to save them but in the process, he himself died by drowning.
Seizo Mochizuki (望月 政蔵, Mochizuki Seizō)[Note 1] and his wife Sae Mochizuki (望月 サエ, Mochizuki Sae) are the parents of Miwa, Yamato, and Sakuzo, and at least one other child. The two of them put great importance on the moon viewing, with their family celebrating it together every year as told to Noboru. This allowed them to live long lives as Seizo died at 101 and Sae at 103 with both of them remaining in good health even past their 100th year.
Kentaro Mochizuki (望月 健太郎, Mochizuki Kentarō),[Note 1][Note 2] deceased at age 85, is a brother of Tsukiji and two other siblings. He married Kayo and fathered Yoshigoro, Seizo, and at least one other child.
Akira Katahira (片平 央, Katahira Akira) is Mai Katahira's deceased husband. He passed his bar exam to become a lawyer. However, he died in a tragic car accident, and died while reassuring Mai that she would be ultimately fine. He has the habit of scratching his head with his pinky finger while sticking his tongue out to hide a failure. He also like canned coffee and used to open it with his pinky. He is named in the TV Drama adaptation of "D.N.A.".
Akira in the TV drama
Akira's mannerism of scratching his head with his pinky finger (Drama)
Sawaki (沢木) is a deliveryman who frequently delivered packages to Mika's apartment.
On November 4, after disturbing Yoma's strict sleep schedule, Sawaki was pulled into Mika's apartment and brutally murdered. Yoma killed Sawaki by severing the carotid arteries in his neck. His body was hidden in the apartment block's underground parking lot, encased in cement.
Hermes (ヘルメス神, Herumesu-shin, lit. "God Hermes"), also represented by many other names, is the god of muscle. Rohan Kishibe believes that Hermes possessed Yoma Hashimoto after seeing wing-like symbols form on Yoma's muscles. After defeating Yoma, Rohan decides to make a run for it, hoping that he hasn't invoked Hermes's wrath.
Mu (ムッ, Mu—) is Eve's pet crocodile, affectionally called "Mu-chan". It is harmless, having a muzzle keeping its mouth shut. It is attacked and eviscerated by Bakin, but thankfully Rohan manages to undo this. Rohan gives Mu to the Yabubako-Hoshi version of Eve.
In the TV drama adaptation, Mu is replaced with a bearded dragon and snake instead.
Emma (恵菜, Ema) is Mitsuki Murase's daughter who attends kindergarten. One day, Emma is left crying alone after kindergarten, and it's up to Mitsuki to pick her up, as the latter is driving the family's only car. Eventually, Emma's father decides to walk over to pick Emma up himself.
Batsudera is a real estate agent who appears only in the OVA adaptation of Mutsu-kabe Hill. He is introduced following Rohan in the mountains and nagging him to convince him to sell his lands, which Rohan refuses. He almost surprises Rohan in the compromising situation of looking like he's killed a little girl.
Maron (マロン) is Kyoka Izumi's 2-year-old female dog. She appears similarly to a Parson Russell Terrier. Kyoka puts her in Taro Hirai's care before she tries to buy a luxurious villa. The gods of the mountain curse Kyoka and it seems that Maron may die, but Rohan manages to make it so the dog is revived.
Ryutaro Todo (藤堂隆太郎, Tōdō Ryūtarō) is a 62-year-old archaeologist and university professor at Tsutsujigaoka University. Affected by the word "kushagara", the professor frantically searches through his books for the word "kushagara" and its meaning. He actually secludes himself in his university office and cuts ties with his family for a month. He dies from nutritional deficiency. Rohan wishes that he could have read the man's life.
Maurice Legrand (モリス・ルグラン, Morisu Ruguran) is a man that is part of an art theft group, whose leader is Ryunosuke Tatsumi. Since Maurice has exceptional skills in reproducing paintings, he is tasked with painting forgeries while hidden in the abandoned underground warehouse Z-13 at the Louvre museum. The group would take original masterpiece paintings from there, then Maurice would create a detailed forgery. The firefighters in the group sent the forged painting to the Louvre's new storage room, while Maurice hid the original painting in the back of one of his other paintings. He then shipped it overseas to Japan, where his gang members would bid on the cheap painting in an auction, so they can retrieve the original painting from the back. Their plan was often successful since Maurice was an unknown painter, so nobody would bid on him overseas.
At some point, Maurice regrets making money from all the forgeries he was creating and tells his group that he wants to quit, but Tatsumi tries persuading him not to since they cannot operate without him. Maurice then comes across Nizaemon Yamamura's Black Painting. In his state of terror, he paints an imitation of the Black Painting, which he calls "Noire", and then dies. Noire is shipped to Japan, where Rohan outbids Watabe and wins it in the auction. Kawai manages to steal it from Rohan but when he peels off the oil paper covering the back, a swarm of black spiders covers his hand before he sees a car appear which runs over him.
It is implied that Maurice committed suicide as Tatsumi feels regret thinking Maurice died because of him. Tatsumi hallucinates the ghost of Maurice from the Black Painting, who strangles Tatsumi to death.
Watabe (ワタベ) is a man that is part of an art theft group, whose leader is Ryunosuke Tatsumi. Along with his partner Kawai, the two would participate in auctions to purchase forged paintings by Maurice Legrand for a cheap price which would secretly have real paintings hidden in the back, which were smuggled out from the Louvre. Watabe competes against Rohan Kishibe for Legrand's "Noire" painting in a Japanese auction. He has the paddle number 9 and raises the minimum bid from 200,000 yen to 320,000. Rohan and Kyoka refuse to give up, so Watabe ends up raising the bid in higher increments again to 500,000 yen and 1.1 million yen. However, Rohan ends up winning in the end with a bid of 1.5 million yen.
Afterward, Watabe and Kawai head to Rohan's house to steal the painting. Watabe stands outside to serve as a distraction, luring Rohan to pursue him. Meanwhile, his partner would go inside to retrieve Noire. Rohan uses Heaven's Door to incapacitate him. Watabe manages to escape after Kyoka screams, causing Rohan to go after Kawai instead. Kawai suddenly disappears after handling the painting, so Watabe tells Tatsumi on the phone that he's backing out since something is off about Rohan. Kawai was not at the arranged escape route and all Watabe saw was Rohan and Kyoka picking up the discarded painting. Believing the job wasn't legitimate, Watabe quickly ends the call after telling Tatsumi that there was nothing on the back of the painting.
Kawai (カワイ) is a man that is part of an art theft group, whose leader is Ryunosuke Tatsumi. Along with his partner Watabe, the two would participate in auctions to purchase forged paintings by Maurice Legrand for a cheap price which would secretly have real paintings hidden in the back, which were smuggled out from the Louvre. During a Japanese auction for Legrand's "Noire" painting, Kawai advises Watabe on the bids he should make. However, Rohan ends up winning the bidding war.
Kawai and Watabe go to Rohan's house after the auction to steal the painting. While Watabe lured Rohan outside, Kawai went inside and shoved Kyoka to the ground, snatching the painting. As he runs away from Rohan, Kawai flips over Noire and peels off the oil paper covering the back. However, whatever he was looking for wasn't actually there. Anxiousness takes over him, as he and his partner just invaded a house and stole the painting for no reason. Kawai notices a black mass resembling tar on the corner of the frame. Suddenly, a swarm of tiny spiders covers his hand. A classic car then mysteriously appears behind him and chases Kawai, who abandons the painting and desperately runs away. By the time Rohan finds the abandoned painting, Kawai and the black mass had disappeared.
Yoshio Kawadori (川鳥義男, Kawadori Yoshio) is an antique dealer from Tsutsujigaoka. Rohan Kishibe's grandmother hired him to organize her storehouse, but he went missing. A week later, the radio reports that his body was found at a scrapped car yard in Kotodai. The cause of death was drowning, despite there being no water around the area. Rohan later realizes that he was killed by the black painting.
Jacques Blanc (ジャック・ブラン, Jakku Buran) is an employee of the Cultural Mediation Department at the Louvre Museum. He is the boss of Emma Noguchi and shares a desk with Marie. Jacques is disappointed about Emma's recent lack of attention at work but still finds her indispensable because of her experience and talents. He reminds her about her task to attend to a Japanese guest, Rohan Kishibe, which she seemingly forgot about. Rohan had questions prepared in advance, but Emma forgot to compile answers. Jacques tells her he'll do it and sends her off since there isn't much time left until their meeting. Emma forwards him the e-mail from Rohan, which asks about Maurice Legrand and Nizaemon Yamamura. Jacques feels as if he heard the name Nizaemon before.
A while after his research, Jacques encounters the black painting. He is caught in its curse and screams. Emma is shocked to see Jacques acting afraid above her in the second-floor exhibition space. Jacques ignores Emma and Ryunosuke Tatsumi, constantly looking back as if he is terrified at something while begging for help, but nobody could see anything behind him. In his panicked state, Jacques jumps off the railing and lands on the floor below, where Emma and Tatsumi rush over to. Jacques manages to tell them about a spider and black hair. Jacques ends up surviving the incident.
Marie (マリィ, Maryi) is an employee of the Cultural Mediation Department at the Louvre Museum. She shares a desk with Jacques Blanc and is stunned in disbelief after an incident where he jumps off from the second floor of the museum, although he survived. Marie tells Emma Noguchi how Jacques was researching about Nizaemon Yamamura before it happened.
Later, Marie finds out that Jacques heard the name Nizaemon from Gaucher Bigotte. She e-mails Emma to let her know.
Samanosuke Yamamura (山村左馬助, Yamamura Samanosuke) is the younger brother of Nizaemon Yamamura. After Nizaemon was disowned by his father, Samanosuke intended to take over the Yamamura household. When Nizaemon was witnessed gathering sap from the sacred tree, Samanosuke files a complaint with the magistrate's office, allowing them to arrest his elder brother.
Chikara Kishibe (岸辺主税, Kishibe Chikara) is an ancestor of Rohan Kishibe and the father of Nanase Kishibe. She is his third daughter. His name is written in Nanase's memories when Rohan reads her with Heaven's Door.