One Piece really threw fans for a loop when it was revealed that Yamato would not be the next main member of the Straw Hat crew as many fans had been asking for, and the newest chapter of the series has Yamato reveal why they decided to stay in Wano in the first place! Ever since Yamato was introduced as Kaido's son in the third act of the Wano Country arc, the fighter had seemed poised to become the next major member of the crew for as much as they had wanted to follow in Kozuki Oden's footsteps and go out to the sea.
As the Wano Country arc officially came to an end and the final saga of the series has kicked into full gear with Luffy and the others heading to their next island, the series took a step back and revealed more of when Yamato actually told Luffy and the others that they wouldn't be leaving the island. Inspired by how much danger came about when Admiral Ryokugyu attacked following the end of the fight with Kaido, Yamato actually decided to stay in Wano to help defend the island from more of these vicious attacks.
Chapter 1059 of One Piece revealed that for as much as Luffy and the others wanted Yamato to join them on their journey, Yamato was adamant about staying behind. Explaining that Ryokugyu was ultimately pushed back by someone's Haki, Yamato realized that even more powerful fighters like Kaido would be using this time to attack the country. It's why Luffy declared Wano to be under his protection as his first big move as an Emperor, and it's ultimately why Yamato wants to be there for what's next.
Yamato can't turn their back on Wano, and knowing Luffy couldn't go on proper adventures with Wano weighing on their mind, Yamato is helping to defend the country from now on! Yamato still very much wants to be a part of their crew (and is technically called one by them), but for now it seems like the series is getting ready for something even bigger coming n both Yamato and the Straw Hats' futures.
How do you feel about this explanation as to why Yamato decided to stay behind on Wano? Do you still hope to see Yamato become a full Straw Hat as the series approaches its endgame? Let us know all of your thoughts about it in the comments! You can even reach out to me directly about all things animated and other cool stuff @Valdezology on Twitter!