We know that Orochi publicly “executed” Oden by boiling him alive. But there are hints that he could have survived:
1-When prisoners arrive in Impel Down, they are put in boiling water known as Hells Hot Tub to disinfect and sterilize them. Ace, Jinbe and Crocodile didn’t even flinch when they went through this. Also, in level 4 of Impel Down the most prevalent form of torture is being thrown into the gigantic pot of boiling blood. So it is possible for strong characters to survive boiling liquids.
2-In chapter 960, Oden is seen drinking boiling food. If he wasnt strong, it would have fried his intestines.
3-It would be stupid of Orochi and Kaido to kill Oden (his knowledge about Raftel, One Piece and Poneglyphs is too important to lose). Yes, he was the son of the Shogun, but it was important to make people of Wano think that Oden is dead. Nobody would question Orochi after that execution and people that loved Oden would lose hope that they could beat Kaido and Orochi.
4-Storywise, Oden is the last member of Kozuki that have knowledge about the Poneglyphs (traditionally he would pass that knowledge to his son but he didn’t have time). So if he is dead, we have lost that knowledge forever. And don’t forget that in the last interview with Oda’s editor we found out that in this story arc we will find out some things about One Piece and Raftel. When you look at all the characters in Wano arc, Oden is the only character that could give us hints about One Piece and Raftel.
So, this is what I think that will happen. In the future chapters, we will find out that Orochi and Kaido are keeping Oden alive and they are torturing him for the last 20 years. But Oden is a badass character and he didn’t say a thing to them about Laugh Tale, One Piece and the Poneglyphs.
Also, I think that Orochi will use Hiyori to get information from Oden (Orochi found out Hiyori’s location in chapter 955, no way he would pass that opportunity to capture and use her).
After 20 years of torture, Oden will finally start to reveal some things to Kaido and Orochi because he will not let them hurt his daughter. But in the middle of all that, Luffy and Co will attack Onigashima and because of the battle, we (readers) will not find out the whole truth about Raftel and One Piece but we will find out some things that Oden revealed before the attack.
What do you guys think about this theory?
*Theory by zure_bih