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|Japanese name:||メアリー 世良 (Mearī Sera)|
|Age:|| Looks approximately middle school aged according to Conan|
Real age is approximately 50s
|Relatives:|| Tsutomu Akai (husband, deceased)|
Shuichi Akai (son)
Shukichi Haneda (son)
Masumi Sera (daughter)
|Nicknames:||Sister from outside the domain|
|First appearance:|| Manga: File 875|
Anime: Episode 756
|Appearances:|| Chapters: 23|
|Keyhole number:||Volume 83|
|Japanese voice:||Atsuko Tanaka|
Mary Sera (メアリー 世良 Mearī Sera) is a middle-school age girl with light hair who has been hiding in various hotels in Tokyo with Masumi Sera. Despite her appearance, she is actually a middle-aged woman; she is the wife of Tsutomu Akai, and the mother of Shuichi Akai, Shukichi Haneda, and Masumi Sera.
Mary Sera is a British woman who married Tsutomu Akai . She bore three children, Shuichi, Shukichi, and Masumi. For some unknown reason, something like APTX 4869 must have caused her body to shrink from that of a middle-aged woman to that of a middle-school child. The change occurred sometime during the last ten years.
Mary's full background is currently unknown. Although Aoyama reveal that she is one of a pair of sisters. Her existence was revealed by Masumi to Conan through an image on her cell phone and the name "The little sister from outside the domain" (ryōiki-gai no imōto). Mary and Masumi currently live in a hotel, and when their position becomes known, they move to a new one. In a recent appearance they seem to be interested in what a TV personality knows about the death of Kohji Haneda and the identity of the missing bodyguard Asaka. Mary has also implied that Conan is no longer the same person that she and Masumi met 10 years ago, lending credit to both the idea that she is a shrunken individual and that they are aware that Conan is Shinichi. Judging on her grown-up appearance ten years prior, the incident where she shrunk must have happened at some point during the last 10 years.
Mary seems very mature and direct, especially when speaking to Masumi. She seems hesitant to trust others at the moment and is being extremely cautious about who knows about her. Currently because of her cautiousness, she and Masumi have been moving from one hotel to another to keep their location hidden.
She is proud of her British heritage.
Like her eldest son she also seems to be clumsy at recognizing the motives behind the feelings of others and how to interact positively with others. In dealing with her children, Mary seems to be strict and cold, treating her children more like coworkers than a family. Shukichi seemed to be more nurturing to Masumi than her mom. When Mary was 10 years younger, she came to physical blows with her eldest son, Shuichi, since he lied to her about his reasons to study in the USA and planned to join the FBI and investigate her husbands' incident. They both went as far as attacking each other's faces, leaving black eyes. She also thought Shuichi, who is a rather cold person as well, would make a good replacement father figure for Masumi and Shukichi. However, soon after she realized that Shuichi was driven by the same sense of curiosity as his father and he would go his own way. To her daughter Masumi, she acts secretively by hiding a lot of important information from Masumi, such as turning off the TV when Shuukichi shogi match was shown, and possibly some other whereabouts of the Black Organization and the Akai family overall. not Her continued mistrust of Conan is another example of her general denseness at understanding others, since it is long past the point where she should be able to tell that Conan's motives and pursuit of justice are genuine.
But she does express joy at Shukichi's victory for becoming the seven-crowned Shogi master. It indicates that she does care for her children.
Mary is a girl of middle school age (12-15) with light colored, curly, neck length hair. The child has eyes similar to those of Masumi Sera and Shuichi Akai. In her appearance in File 877, she was shown wearing a high-neck pleated top, hoodie jacket, and hat. Like all the other manga characters, the color of her eyes is supposed to be blue, as seen in the keyhole of manga volume 83.
In her varying appearances, Mary's eyes have been drawn slightly differently. In her original and current chapter appearances she seems to have an extra lash on the top of her eye, where as in the Pool case and Conan's comparison of her and Haibara's eyes in the Department store case she does not have that extra lash.
Mary seems to know about several types of wire taps. When she and Masumi find Conan's wire tap in their room, she says that she hasn't seen that type before. She also describes the components of it such as its battery life and performance. She spoke in a similar fashion about Conan's voice changer after she gets a chance to use it herself.
She has demonstrated the ability to hang from a balcony by a thin rope/wire and hug the wall like a ninja. Afterword she has the strength to vault back up on to the balcony, much like Vermouth did in the New York case.
10 years ago she already had the ability to fight well enough that she landed a "knife-hand strike" to her son Shuichi's face, who at the time had already been practicing Jeet Kune Do. In the present, even with her small body, she was able to take down a fully grown man by herself. Conan described the damage as "a copped blow to a vital spot, similar to the techniques used by the secret service".
 Plot overview
Masumi asks Conan to find her cellphone by calling it with his. When he does he notices the call background screen is a child with eye bags similar to those of Shuichi Akai and Masumi Sera. He remarks that the girl looks similar to Masumi. Earlier in the case she only mentioned having two brothers; a mother; and a father, so Conan suspects Masumi was intentionally trying to show him the child for some reason.
When Ran, Sonoko, and Conan visit Masumi's apartment, Mary is shown opening Masumi's door as Conan, Masumi, Sonoko, and Ran rush to investigate a crime. It is implied she was hiding in Masumi's bedroom while the other three were in the dining area because Masumi asks Conan not to enter her bedroom. Mary later goes downstairs to the scene of the crime where she is seen by Conan. At some point off screen Conan leaves behind a bug in Masumi's room. After the case is solved, Mary is shown examining Conan's bug along with Masumi, who had found it and crushed it. Mary comments on the quality of the performance of the bug itself and that she has never seen one like it. When Masumi asks if Mary has taken a liking to Conan she says that it is still early to trust Conan, and asks Masumi to introduce her as "the little sister from outside the domain (領域外の妹 ryōiki-gai no imōto)", should Conan question her in the future.
Mary is interested in Shukichi's shogi match. When Masumi returns to the hotel room in the middle of the case while Mary is napping, she turns on the TV and sees the shogi match. Later after the case is solved, Masumi enters the room for a second time to see Mary turning off the TV. Presumably she saw the end of the match and was happy at Shukichi's victory, as was Subaru Okiya, whose identity was revealed in the case before this one, to be Shuichi.
Mary is waiting for Conan to visit her and Masumi in their hotel room. She expresses her still-lingering concern of trusting Conan, even though she thinks he is bright enough. Mary does comment that if anything were to go wrong they would have to move hotels again. Her talk with him alone is put on hold, however, because Ran and Sonoko have invited themselves in accompanying Conan in order to enjoy the hotel's pool. As Conan, Ran, and Sonoko head back home after the case is solved, Ran turns around and sees Masumi talking to her. Ran gets the feeling that she has seen that child before.
Masumi Sera is at Ramen Ogura with Conan, Sonoko and Ran. Katsumasa Ogura asks Masumi (mistakenly calling her "Mari") if she's going to take the same food to her apartment again. Conan implies that Masumi could be giving food to someone she's letting stay in her apartment, making a clear reference to Mary, but she jokes saying that it's for her secret boyfriend. At the end of the case it is revealed that Ogura had found a handkerchief that Masumi had left behind that said "Mary" on it in English. Ogura had confused the English name with the Japanese name "Mari". Conan believes that the handkerchief may be related to the child as well.
Conan thinks about Mary, "the little sister from outside the domain looks a lot like Sera, no wait, more than that girl resembling Sera..." (領域外の妹と名乗る… 世良によく似た… いや… あの子世良というより…‥ ). Conan also thinks to himself that the child's name is probably Mary. At the end of the case Haibara tried to wipe some of the makeup off of her face in the bathroom, but she missed some just below her left eye. The left over makeup made it look like she had the same eye bags as Shuichi, Masumi, and Mary. This causes Conan to make a connection between her and Mary.
Kogoro is put in contact with a Soul Detective who wishes to reveal some information about the Kohji Haneda case. When Conan and Kogoro go to meet with him at a hotel they find him dead and that Masumi and Mary have mysteriously moved in to the next hotel room. During the investigation Conan runs into Masumi's hotel room and checks the balcony. Mary has hidden herself by anchoring herself to the balcony and hiding by hugging the wall underneath it. Conan nearly discovers that she is hiding there by trying to take a picture over the edge, which startles her. Conan then drops his voice-changer on his way back inside. Mary picks it up, and later uses it in place of Conan to solve the case. When the culprit tried to flee, Mary was able to take him down single handed using skills comparable to that of the secret service. Masumi calls her "Mama". Once Conan had left, Mary and Masumi discuss what information the Soul Detective had, which was that before Kohji's death, Asaka was seen holding a hand mirror and thinks that it means that Asaka is a woman. Mary warns Masumi about Conan saying that "it is like encountering a demon in the darkness" (暗がりに鬼を繋ぐが如く), and that he is not the same boy they met 10 years ago. Conan goes home and theorizes that Mary could have been Asaka. Later Gin uses the same demon line that Mary used to refer to Kogoro.
10 years ago at a beach somewhere in Japan, Shuichi reunited with his family after his 7 years in the US. Mary had an off-screen fight with him where they both managed to injure each other's eye. Through out the case Mary warns him to stop investigating the disappearance of his father. She also tells both Shuichi and Masumi not to do things that got them involved in the case, because there are people out there that are after them.
After the case is solved, Masumi calls Mary and informs her about the drug that will returns her back to normal, after witnessing Shinichi's appearance. Mary ordered Masumi to find the developer of the drug and obtain it. Once she succeeds, Mary declared that they will stop running from hotel to hotel and counterattack.
 Non-Canon Plot Overview
 Movie 18: Dimensional Sniper
Mary is only shown two times at dawn under her hotel bed's blankets.
 Tsutomu Akai
Tsutomu is her husband, who she lost around 17 years prior to the series. In his last message, he advice them to hide in Japan and think of him as dead due to that he has made himself some enemies.
 Shuichi Akai
Shuichi is her oldest son. She didn't approve at first of his decision to join the FBI and investigate his father's death, but eventually she gave him her blessing.
 Shukichi Haneda
Shukichi is her second-oldest child and youngest son. It's not certain how she feels of him, but she keeps track of his Shogi-career and seemed happy when he became the seven-crowned king.
 Masumi Sera
Masumi is her only daughter and youngest child, who born after the family moved to Japan. Currently the two of them switch between hotels to hide themselves.M Mary seems to act cold towards Masumi and doesn't trust her entirely.
 Haneda Kouji
Mary reacted to Kouji's name when she heard Kogoro mention it. It's possible that the Akai family, including Mary, might know Kouji in person.
 Plot Exposition
 Hints that Mary is the Akai family mother
These were the hints that fans used to determine that Mary was the Akai family mother prior to the end of the Soul Detective Murder Case where Masumi called Mary "mother", and the flashback to Shinichi and Ran meeting the Akai family on a beach.
- Mary shares a resemblance to Shuichi Akai and Masumi Sera, and it was known from Masumi's earlier testimony that Akai family's mother also passed her looks into Shuichi and Sera.
- Mary is unusually mature while talking to Masumi. She gave Masumi instructions despite Masumi being apparently older and a skillful detective in her own right.
- Mary was happy when Shukichi (who was later revealed to be the middle brother of the Akai Family) won his 7th Shogi title.
- Mary seems to have some knowledge abut wiretaps, she also demonstrated the ability to a balcony by a thin rope/wire and hug the wall like a ninja. She was also able to take down a fully grown man by herself. Conan described the damage as "a copped blow to a vital spot, similar to the techniques used by the secret service." A normal middle school girl wouldn't be able to do this.
At the time Mary was introduced, her relationship to Masumi Sera was unknown. Masumi testifies that she has two older brothers: Shuichi Akai and an unknown brother (later revealed to be Shukichi Haneda) living in Japan. She says her father is dead, and her mother lives overseas in America. Masumi says she doesn't have any more relatives close enough to depend on. Masumi only started claiming to have a "younger sister from outside the domain" after the unknown child coached her to use that cover story if Conan asked about her. She is currently being financially supported by a friend of her father's. If Masumi has told the truth, minus what she said about having a "younger sister from outside the domain", that leaves relatively few options for Mary's identity assuming the child is related by blood somehow to Masumi. In file 972, Mary is revealed to be the Akai family's mother.
 Mary is an adult shrunken by APTX 4869
Mary acts like an adult despite having the appearance of a middle-school aged female. When Masumi and Mary speak, the speech honorifics are not those appropriate for an elder Masumi talking to a younger girl. Instead, they appear to indicate the two are on equal levels, or even reverse with Mary expressing greater seniority. In addition, Mary's Voice actor in the anime, Atsuko Tanaka, has a deep and sultry voice which is often used to portray mature female characters
The secrecy surrounding Mary, as well as Masumi's attempts to get her to trust Conan, whom Masumi knows is a shrunken Shinichi, might be indications that Masumi is trying to get the child help about an APTX 4869 problem. Mary appears to be sickly and is often seen coughing. This could be a side effect of an earlier version of ATPX she may have ingested.
This very popular fan theory was born after Gosho hinted that two mother characters are sisters. After it was confirmed the sisters were not the previous most popular choice Yukiko Kudo and Chikage Kuroba, and that the Akai family mother was one member of the sister pair, fan suspicion fell squarely on Elena Miyano as the other mother. After all, the two are both British. Gosho has given evasive answers when asked about Elena and the Akai family mother being related, which is his habit when a fan theory is correct but he can't admit to it. 
 Mary is a British SIS/MI6 Agent
Mary is British and has several unusual skillsets that match those of other spy-like characters in Detective Conan. Mary has knowledge of incapacitating martial arts that can bring down adult men despite her size, extraordinary flexibility and climbing skills that allowed her to hide below a balcony like a ninja, and knowledge of listening devices and hidden microphones. Because of her British nationality, the theory that she is a member of the British Secret Intelligence Service, often known as MI6, has gained traction in many Detective Conan fandoms.
 See also
|Rum arc topics|
|Main interest||The Boss of the Black Organization • Renya Karasuma • Rum • Case from 17 years ago|
|Connections||Kohji Haneda • Asaka • Amanda Hughes • Tsutomu Akai|
|Related Articles||APTX 4869 • APTX 4869 Victim list • Rum arc timeline|
|Cases of interest||The Scarlet Return • Three First Discoverers • The Detective Boys in a Grove • Just Like a 17 Years Old Crime Scene • Soul Detective Murder Case • The Stage of Betrayal • Burning Tent Murder Case|
- ^ Akai is 31-32 (SDB90+ Q4) so add ~18 years on that at reasonable minimum.
- ^ a b c d e File 974
- ^ a b c d File 972
- ^ a b File 953: As If Connecting with a Demon in the Darkness (Volume 90)
- ^ a b File 952: In the Suspicious Next Room (Volume 90)
- ^ a b File 930: Excessive Seasoning (Volume 88)
- ^ a b File 903: The Corpse in the Pool (Volume 85)
- ^ File 953
- ^ Manga Volume 82, File 11 (872), pg 3: Red Woman. "We're three siblings: My two oldest brothers and me, their little sister!"
- ^ Manga Volume 83, File 4 (876), pg 3: "The Romance Novelist"
- ^ Manga Volume 83, File 6 (878), pg 16: "The Phone, the Sea, and I" She requests Masumi call her the younger sister from outside the domain if Conan asks
- ^ Manga Volume 83, File 7 (879), pgs 2-3: "Detective's Master" Conan asks about the girl and Masumi uses the "younger sister from outside the domain" explanation as she was instructed. Conan notices the discrepancy between this and her earlier statements which didn't mention a sister.
- ^ Episode 759 1min 41sec Crunchyroll translation: "If she has two brothers and doesn't know of her relatives, then who is that young girl I saw on her phone that looks just like her?"
- ^ According to polls at DCW as of Sep 10, 2015, the most popular choice for her true identity is APTX-dosed Akai family mother
- ^ Leaked interview notes from the May issue of the magazine 「ダ・ヴィンチ」 (da Vinci) with the fans/reporters/whatever, leaked April 15, 2014
"Two mothers will also be revealed as being sisters, etc.…… A lot of things are connected together. This is bad, I'm talking too much. Well, please look forward to the manga."
- ^ Super Digest Book 70+: Gosho Aoyama's Interview
"Are Yukiko and Sera's mum sisters?"
Answer : The sister isn't Yukiko but...
- ^ When answering fan questions, Gosho often bluntly says "no" if a guess is wrong. If it is correct and would spoil a mystery, Gosho's habit is to be vague and avoid giving a firm answer rather than lying or giving in and revealing the truth. After narrowing down the choices, fans started trying to trap Gosho.
Conan Super Digest Book SDB 80+
Q5: Are Elena Miyano and Shuichi Akai's/Sera's mother sisters?
A: Eh? Why's that?
Q62: Are Sera and Haibara cousins?
A: Stop asking in a roundabout way, I'm not going to get tricked! (laughs)
- ^ Soul Detective Murder case
- ^ Soul Detective Murder case
- ^ Romance Novelist Murder Case