Given the things we know the traitor revealed to the enemy and the timeline of events Kanjuro is the one that makes most sense. So let me go over a few points.
1-Jack learned 2 things from the traitor – how to get to Zou and the fact that Raizo was there, back when this was revealed most people suspected that a mink was a traitor, but Kanjuro could have provided them with this information as well. The samurai had a way of getting to Zou (probably Inuarashi or Nekomamushi’s Vivre Card), and Kanjuro knew that Raizo ended up there. Add to this the fact that his ability would enable him to send messages (and the Vivre Card) using his painted creatures.
2-After he was “captured” by Doflamingo’s men he spent the next few weeks just sitting in a cell, he wasn’t sent back to Kaido or anything? Kaido sent an army led by one of his top men to get Raizo but he just let Joker hold on to Kanjuro?
[Kanjuro could be a deep spy like Apoo once was with the Kid and Hawkins alliance.]
3-The first time the traitor revealed the Alliance’s plans in Wano it could have been anyone, but the second time among the information revealed was the fact that Hiyori is alive and in Ringo, not many people are privileged to that information – Zoro, Kawamatsu, Kin’emon, Raizo, Kikunojo, Inuarashi, Momonosuke, Tenguyama, Kanjuro and some other Straw Hats (some other characters may have learned it off screen but that is not relevant). Through the process of elimination and considering the points 1 and 2, Kanjuro stands out as the most suspicious.
In chapter 920 we have the ultimate proof that Kanjuro is the traitor.
In the panel showing Kinemon & co. landing in Wano 20 years later, we can see two small and horrible birds flying above them. Did Kanjuro draw them? Were they sending a message to Orochi/Kaido?
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1-Jack learned 2 things from the traitor – how to get to Zou and the fact that Raizo was there, back when this was revealed most people suspected that a mink was a traitor, but Kanjuro could have provided them with this information as well. The samurai had a way of getting to Zou (probably Inuarashi or Nekomamushi’s Vivre Card), and Kanjuro knew that Raizo ended up there. Add to this the fact that his ability would enable him to send messages (and the Vivre Card) using his painted creatures.
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2-After he was “captured” by Doflamingo’s men he spent the next few weeks just sitting in a cell, he wasn’t sent back to Kaido or anything? Kaido sent an army led by one of his top men to get Raizo but he just let Joker hold on to Kanjuro?
[Kanjuro could be a deep spy like Apoo once was with the Kid and Hawkins alliance.]
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3-The first time the traitor revealed the Alliance’s plans in Wano it could have been anyone, but the second time among the information revealed was the fact that Hiyori is alive and in Ringo, not many people are privileged to that information – Zoro, Kawamatsu, Kin’emon, Raizo, Kikunojo, Inuarashi, Momonosuke, Tenguyama, Kanjuro and some other Straw Hats (some other characters may have learned it off screen but that is not relevant). Through the process of elimination and considering the points 1 and 2, Kanjuro stands out as the most suspicious.
You must be registered to see images
In chapter 920 we have the ultimate proof that Kanjuro is the traitor.
You must be registered to see images
In the panel showing Kinemon & co. landing in Wano 20 years later, we can see two small and horrible birds flying above them. Did Kanjuro draw them? Were they sending a message to Orochi/Kaido?