Rellik wrote:
lol i can see ppl getting their fingers ready to spam this thread full of what we know about the BO boss in the oncoming arc ;D
I'll take your offer.
Because I'm too lazy to copyedit my speculations document, some of the same stuff as posted above will be repeated, but I go into more indepth analysis. Lack of indents make me unhappy.
What is known about the boss and what conclusions and reasonable assumptions can be made about this person?
From the extra Detective Conan book:
1) Aoyama had already put the name of the boss somewhere on the manga in some form or another. If I knew when this quote was made, then I could narrow it down to chapters before this point. It’s at least before chapter 644 due to the book’s publishing date, but likely much earlier than that. Some of Aoyama’s Gosho’s interviews place back to around chap 560 or so.
2) Aoyama suggested that the true name of the syndicate, which has also never been revealed, is tied to the identity of its leader. If the Black Organization's real name were revealed, everyone would know who its leader is. This seems like a pretty big hint. I strongly doubt Gosho would do something as direct as naming the organization after the bosses’ last name. Given the organization’s use of classic literature, especially of the mystery genre, and allegory, the organization’s true name is probably a clever reference or a play on words. (Heaven forbid it's a pun)
3) Aoyama also said that Ai would be really shocked if she discovered who the boss is. Ai is very paranoid and untrusting, so the condition that the identity of the boss would really shock Ai helps narrow down the cases. She obviously knows who this person is otherwise the boss’s identity wouldn’t catch her off guard. The shock factor would increase if she met the person at least once without knowing his/her true identity. I came up with several possibilities:
1) She trusts this person dearly. There’s a pretty limited number of people that fit this criteria and most of them seem to be dead or are protagonists and therefore very unlikely to be the boss.
2) The person wouldn’t fit Ai’s expectations
2.1) The person seems "useless" or of unsuitable personality to actually think of them as being a mastermind behind a large organization. Ai would have had to meet this person personally so that she could gauge their personality and subsequently write them off as unlikely to be anyone of consequence. This person would almost certainly not trigger Ai’s “black org sense.”
2.2) The boss’s front job or status is unexpected like a policeman or a school teacher rather than a scientist, company boss, or political figure. It would have to be an unusually benign front to really shock Ai. This person would probably not trigger Ai’s “black org sense” either.
2.3) The boss is relative of someone close to Ai. This is the “evil relative theory”; one of the protagonist’s relatives is the boss or has a direct connection to the boss. The unlikelihood that the honestly good protagonist has some sort of connection to the head of the evil syndicate makes it shocking. The boss could also literally be Ai’s blood-relative, but considering her family’s underworld connections, I’m not sure that Ai is naïve enough to assume that one of her relatives couldn’t be the boss.
2.4) The person's age is unexpected. Given the aging wonkiness that has gone on there is a possibility that the boss could even be a “child” somehow mucked up by drugs or whatnot which would explain why the boss only uses email to avoid allowing people to hear his/her youthful voice and avoids letting people meet him/her although this behavior can simply be explained as generic cautiousness. In this case, Shiho wouldn’t need to have met the boss before to be surprised.
3) She thinks this person is dead. Her parents would be an example of this, although that means they ordered the death of both of their daughters. Shiho’s mom seems unlikely to do so based on the tapes but background on Ai’s father is minimal.
Personality/Background
1) The syndicate leader uses the song “Seven children/ Seven year old child” to encode his/her email. It is likely the Boss is probably Japanese, grew up in Japan, or had Japanese parents, relatives, or spouse as this children’s song is not well known elsewhere. Do the contents of the song reveal something? Does the boss have children?
2) The operatives dress in black, which Akemi says is supposed to resemble crows. This is probably an expression of the boss’s dress code preferences. This seems like is might be related to Nanatsu no Ko.
3) Uses alcoholic codenames.
4) The organization uses clever codenames, passwords, etc. based on mysteries and history. If the boss is behind the naming scheme then perhaps the boss has an interest in detectives and mysteries.
5) The org has ties to America although the only overseas components occur before the current storyline. The involvement of the American intelligence agencies is testament to this. Perhaps the boss has spent some time in America as well, although that’s not a requisite.
Boss’s opinions/relations
1) Vermouth is the boss’s favorite so he/she allows her some independence and overlooks some of her potentially dangerous behavior. It’s confusing why Vermouth is the boss’s favorite when she actively engages in behavior which is encouraging the syndicate’s downfall - like protecting Conan and allowing Ai to escape. I have a hard time believing the boss could not see her traitorous intent. Obviously Vermouth has some characteristic that makes up for her actions. (The failure to age possibility?) At the same time the leader can also command the absolute respect of a wildcard like Gin who vocally despises traitors. Why would Gin follow a person who tolerates rogue agents like Vermouth? All of this makes me wonder what exactly makes Gin so loyal. Whatever the reason, the boss clearly knows people well enough to balance these contradictory personalities and their agendas successfully.
2) The Boss thought Akai Shuuichi could become the org’s silver bullet. (434) In that regard he/she's more like Vermouth than Gin who doesn't believe a single person who can take the syndicate down in one shot exists.
Location
The infamous Nanatsu no ko number has a Tottori area code. In the star case in 45-9, Haibara reacts to the word Kurayoshi – a city in Tottori province. (466)
Age
The organization has been around for over 50 years. (file 189, but see the ep 130/131 for a better translation) If the boss has been the same for those fifty years, assuming the boss started the organization at around 20, that would put him/her at 70+ years of age.
As a bottom end estimate, Haibara grew up within the organization and she hasn't mentioned there being a changeover in bosses. (not that she mentions much of anything regarding the org) Assuming she remembers things from when she was 6 or 7, that would put the boss at around 30 years at a minimum; however, due to aging wonkiness, the boss may not appear to be as old as he/she is.
i have some ideas of who the boss could be:i think about agasa,he knows ai's parents,and it's also him who said to shinichi to not talk about the org.even with ran in vol 1.i also think about ai's father since we don't know much about him,even with the tapes of ai's mother,unlike his wife,he didn't gave any memory for ai,althought he knows that he will be killed,so maybe he's alive.and finally i suspect yusaku,cause unlike yukiko,he didn't met ai so we don't know how she'll react,moreover,in vol 19 the computer program have the same name as the character in his books(night baron,or something like that) but i'm sure that the boss will surprise us! 
