In the last chapter Oden explains the meaning of opening Wano Country’s borders.
Oden tells the Scabbards to somehow open Wano’s borders so that a certain someone can come and liberate the world. It seems like he is talking about Joy Boy.
Oden knows that Orochi will not let him live so he uses his full might and pushes all the Scabbards out of there so that they can escape and open Wano’s borders someday.
In the meantime we find out that Kaido didn’t cheat Oden in their fight and was extremely angered by the interference of Kurozumi Higurashi. Kaido in fact reveals that he killed Higurashi prior to Oden’s execution.
And we understand how much Kaido respects Oden.
Kaido realized that Oden’s body was done even though he managed such an incredible feat and going out like this was probably one of the most honorable and dignified ways he could have died given the circumstances. He knew Oden couldn’t have given him another fight like they’d had 3 days prior. Kaido even giving Oden a chance to survive the boiling in the first place was an understanding between 2 warriors. Orochi would have never allowed such a thing.
Oden died a legendary death, just like Whitebeard, and you can see just how hard this hit the Scabbards in particular. To them, he was more than just a leader, he was like a father figure who protected them to the bitter end, much like Whitebeard.
Both Oden and Whitebeard died on their feet protecting their family betrayed by those they welcomed.
Furthermore, Toki sending her son and some of his retainers twenty years into the future is revealed to be instructed by Oden.
A giant war will start in 20 years and someone will come and defeat Kaido then.
So Oden’s prophecy has come true and Luffy is here to defeat Kaido. We thought Luffy will have help defeating Kaido but it seems like Luffy will 1 vs 1 Kaido alone and defeat him.