So yeah whats the purpose of yamato and what is his role in wano and afterwards?
Oda introduced him pretty suddenly and late into the arc too which makes it kinda weird
In Wano I think Oda is going to use Yamato in tandem with Momo to comment on inherited wills. Where Momo can’t live up to his fathers legend and caves under the pressure. Yamato strives to spite her dad and become “Oden”. Oda has set up some interesting parallels between Kaido, Oden, Yamato and Momo.
I also think that Momo will grow character wise when he confronts Yamato and tells her that she’s not Oden and that neither is he(Momo himself distancing himself from his fathers legend). Together they’ll face the “resurrected” Orochi. Yamato is probably stronger than Orochi but we’ve yet to see the capabilities of his devil fruit and he is craven so he’ll probably fight dirty.
This guy will probably be involved too.
Post Wano though, most people think Nakama.