Chapter 962 just revealed that Oden had a logbook that he recorded in his travels, something of which he treated as a diary, and – given that Oda rarely shows something without purpose – I believe this logbook serves a big role and significance in this arc…
It also seems likely that Oden – given that he was part of Gol Roger’s crew – may have also recorded and penned his experiences with the Roger Pirates in the journey to Raftel. In other words, Oden’s logbook could in fact, be a map to Raftel(Laugh Tale), and I strongly suspect this is what Kaido is looking for, which is why he remained in Wano in these past 20 years…
Just to refresh our memory, Kaido invaded Wano and killed Oden, allowing him to assume rule of Wano and allow Orochi to become Shogun for 20 years. The question is, why did Kaido invade Wano? And the answer is simple.. each generation of the Kozuki family – with the exception of Momonosuke – could understand the languages detailed in the Poneglyphs.
And so if Kaido managed to force Oden to become his own personal translator, he would be one step of the competition, and I believe this was Kaido’s original plan, as he already had a Road Poneglyph, but for obvious reasons, this plan never worked. So the question remains – given that Oden died and no-one knew Momonosuke was still alive in these past 20 years, Kaido still remained in Wano. Why is that??
I believe it’s because Kaido somehow, had information that Oden had a logbook, and if Kaido had such an item in his possession, he will be miles ahead of the competition and actually get to Raftel – a shortcut – without ever needing the other Poneglyphs. This is also a subtle reminder of Baratie, where Don Krieg wanted Zeff’s log in order to safely traverse the grand line.
Other than this item being a map of Laugh Tale, it could also highlight Oden’s experiences when he was part of the Whitebeard Pirates… it could perhaps even contain other info, such as how Roger was able to get him into his crew, or even more.. additional information of the D. people, which has still continued to remain a mystery in One Piece for 900 chapters now.
The next question I’ll address is this: Assuming Kaido has been trying to get this diary/logbook for 20 years and still never managed to obtain it, where is this logbook now? Who has it? How has it remained hidden for all these 20 years?
The answer I’m willing to bet on, is that Orochi had Oden’s logbook all along.. but never gave it to Kaido, because of these reasons:
1. He knows he will be untouchable if Kaido is there to protect him…. Without Kaido backing him, his reign as Shogun would’ve been over as soon as it started… If Orochi could keep Kaido in Wano to protect him as he did 20 years? No-one could touch him.
2. Given Orochi’s sly and cunning personality (which was really highlighted in chapter 962), it makes a lot of sense for him to actually hide such an item from Kaido, for his own selfish benefit.
The question pertains: How did Kaido know of such a logbook? I’m willing to believe Orochi betrayed Oden by informing Kaido of a logbook Oden recorded in his travels. This could be the reason Kaido boiled Oden as a torture method in order for him to spill the beans to where it is.
*Theory by Suppiluliuma