In chapter 983 Yamato appears for the first time, saving Luffy from Ulti and escaping with him.
Many fans have noted the suspicious similarity between Yamato and Oden. Let’s look at the similarities:
-Both have the “ribbon” at their waist. Both have some very strange handcuffs.
I think Yamato is someone who knows the real history of Wano. He probably read Oden’s Diary. He knows and therefore honors the history of Wano by wearing the clothing of someone who tried to save Wano. He honors Oden by essentially “cosplaying” the most honorable person he knows. That’s my idea on why he is dressed how he is.
-Very similar body structure and movements.
I don’t think Yamato is Oden, due to Oden’s body being totally destroyed by the burning oil. As the Scabbards fled, Kaido shot Oden in the head and Oden died with a smile.
-Both have the incredible desire to escape the island, we know Yamato had run away on different times.
Yamato is obviously going to be an ally now, and I think there’s credence in the belief that he’s been waiting for Luffy to help him escape the island. There might even be some potential for him to join the Straw Hat Pirates crew. We’ll see.