One Piece S21 E1013 Yamato’s Past! The Man Who Came for an Emperor of the Sea!

"Set sail for One Piece!"

Yamato tells Momonosuke and Shinobu that he once confronted a man, who came to Onigashima looking to get Kaido’s head. His name was Ace. The two of them engaged in a fierce battle that eventually turned into an important friendship.