...About why Zexion's book can are major spoilers (Nomura said it himself).
It's just a thought I had, so don't think it's official 'cause it's not, but let's go for the topic.
Nomura once said (before KH2: FM+) he couldn't reveal Zexion's weapon because it would be major spoilers, so today I came up with this: Zexion weapon is a book nothing new, but if you look on it's cover you'll notice that there are 3 symbols of the nobodies (check here YouTube - Kingdom Hearts 2 Final Mix + Zexion Data Boss Fight in the very beginning 00:06 - 00:07).
Yen Sid also has a book but his has only 2 symbols (check here YouTube - French Kingdom Hearts 2 - Yensid Tower (1st part) 06:35).
This made me think that maybe Yen Sid happened to be Ienzo's (Zexion's) master sometime in the past, maybe even before Ienzo become ATW apprentice. What I'm saying is maybe Ienzo was an apprentice of Yen Sid and learned all he knows about spell casting with YS maybe during the time of BBS or a bit before, so he knew all that was happening and after his training was complete he joined ATW and told all he knew specially to Braig (Xigbar), that would explain why Xigbar seems to know so much about VAT and the BBS happenings (attention this wouldn't explain why he knows about the rooms of sleep and awakening, this info maybe Xehanort gave to Xigbar but focus on the topic forget about the rooms), that would also explain why Zexion is number 6 in Org: he was the last one to join ATW therefore he is the last numbered among all th apprentices (6 apprentices = Org. number 6).
The numbers of symbols could mean how "old" they are, in other words, Zexion's book came after Yen Sid's and his came after another magic book, this book could be another of his own (purely about spells) or someone else's book (MX's?????).
Conclusion: the book is a spoiler once, assuming all I said is true, it is a clue showing connections between YS, Ienzo and probably MX and answers to some questions that there are.
This is my theory tell me what you think about it.
It's just a thought I had, so don't think it's official 'cause it's not, but let's go for the topic.
Nomura once said (before KH2: FM+) he couldn't reveal Zexion's weapon because it would be major spoilers, so today I came up with this: Zexion weapon is a book nothing new, but if you look on it's cover you'll notice that there are 3 symbols of the nobodies (check here YouTube - Kingdom Hearts 2 Final Mix + Zexion Data Boss Fight in the very beginning 00:06 - 00:07).
Yen Sid also has a book but his has only 2 symbols (check here YouTube - French Kingdom Hearts 2 - Yensid Tower (1st part) 06:35).
This made me think that maybe Yen Sid happened to be Ienzo's (Zexion's) master sometime in the past, maybe even before Ienzo become ATW apprentice. What I'm saying is maybe Ienzo was an apprentice of Yen Sid and learned all he knows about spell casting with YS maybe during the time of BBS or a bit before, so he knew all that was happening and after his training was complete he joined ATW and told all he knew specially to Braig (Xigbar), that would explain why Xigbar seems to know so much about VAT and the BBS happenings (attention this wouldn't explain why he knows about the rooms of sleep and awakening, this info maybe Xehanort gave to Xigbar but focus on the topic forget about the rooms), that would also explain why Zexion is number 6 in Org: he was the last one to join ATW therefore he is the last numbered among all th apprentices (6 apprentices = Org. number 6).
The numbers of symbols could mean how "old" they are, in other words, Zexion's book came after Yen Sid's and his came after another magic book, this book could be another of his own (purely about spells) or someone else's book (MX's?????).
Conclusion: the book is a spoiler once, assuming all I said is true, it is a clue showing connections between YS, Ienzo and probably MX and answers to some questions that there are.
This is my theory tell me what you think about it.