Recently, it was revealed that Shanks has ties to Wano. Shanks held Oden in high regard as he wanted to help him make Wano Country open to the world though Oden declined the offer. Oden in turn, referred to Shanks as the first son.
Well Momonosuke is Oden’s son, and Luffy is in Wano as well. I can’t see Shanks just letting things play out. Furthermore on Onigashima the 2 Yonkos Biig Mom and Kaido have formed a pirate alliance in Wano.
I think Shanks is going to show up and fight Big Mom (and his crew versus her crew), allowing Luffy, Kid, Drake, Hawkins and Law to team up and defeat Kaido and his crew with help from Samurai and Minks.
I don’t believe Big Mom would be dying or anything, I feel like Kaido might go down this arc, while Big Mom lives, but is put into a position where she truly might have a depowering of her kingdom, maybe with Marines running through while she’s gone, and she’ll be with just a small core crew and will become a sort of ally going forward.
I feel like this all makes sense since Shanks has to have a moment where he shines before his death battle. I feel like this battle will show off what Shanks can do.
It will also give him a nice moment with Momonosuke and Luffy.
So yeah, this is the fight in which Shanks really shows the extent of his powers, then a little down the line, he’ll be killed by Blackbeard.
*Theory by HopOnTheHype