Somewhere Zoro & Ryuma are related and I believe that Shusui will return to Zoro again, people of Wano may witness spirit of Ryuma this time.
I want to build a theory around this topic on next power up for Zoro considering the fact that YAMAO matched Yonko in the fight, even Sanji has shown sign of a new upgrade.
Just a theory which I want to build up before spoiler is out but due to short of time, I might not be able to put more details into it.
Will try to complete it by adding more information later.
Thank you 😊
A good theory, hope to see more.