I guess yamato will be the one to visit ryuuma's grave in a cover story or smthing
(three weeks later)
Yamato: "Hyaaaaaaa!"
The Straw Hats approach Wano, and see Yamato cutting battleships apart with ease, while dual wielding swords.
"Oh! Hi guys! I visited Ryuma's Grave while you were gone, and studied ancient swordsplay! Now, I'm the strongest swordsman in the world! I just beat this guy named
'Myhawk, or something'!"
(Mihawk has lost an arm and is unconscious at Yamato's feet)
"Hey, Zoro, why don't you stay and guard Wano while I go to Laugh Tale! Luffy said he only wanted the World's Strongest Swordsman, right?!?"
(Zoro cries on the shores of Wano, as Yamato laughs with the crew while saying to Elbaf)
Wano: End