Sequence of events ( my headcanon)
- Yamato witnessed the finest hour and is inspired by Oden and chose to become him
- Yamato went to Kuri and found Oden's journal
- Ace arrives in Wano
- Ace meets/befriends Tama
- Tama tells Ace about Kaido and Orochi
- Ace gets pissed and wants to challenge Kaido
- Ace arrives at Onigashima and instead fights Yamato
- Ace beats Yamato, so Kaido wants to recruit him as HIS ace
- Ace refuses and gets thrown in Udon. Yamato visits him, hears the story about Tama, learns about Luffy and Sabo, befriends and then frees Ace
- News of Ace's execution somehow reaches Wano (if Orochi can contact CP0, they must be able to get news from the WG)
- Yamato pleaded with Kaido to save Ace
- Kaido begrudgingly agrees, because he wants to impress his daughter
- Kaido is stopped by Shanks enroute to Marineford
- Ace is killed
- Word of Luffy ringing the bell at Marineford reaches Wano
- Yamato knows Luffy has to travel to Wano for the poneglyph to reach Laftel because she had read Oden's journal, hence why she said she was waiting for him