Ai Haibara's grandfather is "anokata" or the boss of BO

[Retro 1]

Well I was thinking If the character that is the boss has been shown or mentioned in the series a few times and once that person is reviled haibara will be shocked. So we can narrow down the characters to six people. Haibaras family (Father, Mother, Sister and grandfather), Shuichi Akai and Agasa. It cannot possibly be Agasa because the boss wants Haibara dead and Agasa is like her guardian which he could've killed her long ago. It can't be Akai because he is deeply in love with her sister and has saved her in the previous BO action on the train. (Subaru is Akai). It can't be her sister because she has died by the hands of the org. Now It can't be her father or mother even if there is no proof of them dead but they are just to young to be the boss. The BO has been for 50 years now and her father should be around 54 years old because his best friend was 54 years old but then again his age is unsure. So I have no proof of them being the boss. On all these facts I say that boss is haibaras grandfather. I do not have any clue of him being dead or alive. Or him being mentioned in the series. But if you go now and check the page on this site about Atsushi Minayo (Haibaras father) and scroll down a bit to his relatives. It does say that he has a father but it's unnamed. Now his age is enough to be the boss because he should be about 60-70 years old. And if your thinking that he should be dead due of old age then no, why you ask? Well because vermouth is the boss's favorite subordinate and she has never changed her appearance even that she is old and she has been able to fake her death as Vinyard and look young always. With some kind of drug both her and the boss can stay young for a while. So this could be a reason why vermouth is the boss's favorite subordinate. And mostly bosses of secret organizations are ruthless and will kill anyone that gets in they're way including they're relatives. So wanting to kill her niece cause she left the org and let out a lot of secrets is not weird at all. So this is my theory on the boss of the black organization. And the organizations name should be The Miyano Org or something related to that name that's why Gosho didn't tell us the org's name because the boss's name will be reviled.

[Quol 6]

Well i think you have a point that the boss might show up in the series undercover at one point. The name of the organization would not be something that obvious though since they work in secret if their name was something that pointed a neon arrow at the boss it would be very contradictory to their MO.

 

While i do think that the grandfather is a possible suspect to be the boss, the series is far from over and we will get much more characters introduced. So until then i would say this is a good theory.

[Retro 1]

Thank you @Quol!

[ranandshinichi4eva 14]

I believe it was stated by Gosho Aoyama himself that Agasa is not the boss for the Black Organization. I also read in a guidebook I got a few years back that even Ai Haibara would be shocked who the boss of the organization would be. So assuming that's correct, I believe that the boss has to be someone who is acting like a member of the BO to see what his lower rankings are doing, or it's someone who is really good at giving off a good vibe. 

[moroboshi dai 11]

i don,T think its any AI relative as it will be to easy to pinpoint him/her 

i believe its someone we don't know he/she have a link to haibara at the moment like anyone she haven't met yet 

[Retro 1]

That is a possibility as well.

[Vermouth02 0]

Gosho said in an interview that the Black Organization's boss already appeared in the series. But he ruled out Dr. Agasa. If he said that Ai Haibara would be surprised to know, maybe it's someone only to close to her? Since Gosho didn't say that 'They' will be surprised, since he only used Ai Haibara?

[kyriesaur 3]

The boss already appeared? On what episode? why Haibara Ai didn't feel anything to it? :/ 

[Nara-chan 38]

Correction: manga. (Not sure for anime)

 

 Aoyama-sensei already said that the boss' name had already appeared in the manga. (Whether or not he had appeared in person is unknown)

[HellAngelsDaughter 1]

If Ai is the most person whose going to be surprised or affected who the boss is then its probably related to her or somehow in a connection with her. 

 

I feel like some of her family may still be alive.. Oh well the story is still developing up until now,  more characters is probably will be introduced..