This is easily the best chapter of the flashback, thus far. It's nice to see the contrast between the Scabbards at the start of the chapter and at the end. They were a rowdy, unorganized group, with no set plans.
But then that fantastic montage reel of them making all those improvements, both as individuals and fighters hammers home the devotion they hold for Oden. Which brings me to the overarching themes of the arc; loyalty. Everything down to Luffy's alliances, the traitor, Big Mom/Kaido's alliance, Orochi's betrayal, etc, they all coalesce to the idea of loyalty and fealty. And Oda has this crafted around the motif of historic Japan. A time of Samurais, Ninjas. Where this very concept of duty and honor are tantamount. It's amazing. The 9 Red Scabbards and Oden themselves are kind of like a proxy of the Strawhats. The words echoed by Yasu drive this home.
The Strawhat Pirates will work hard towards becoming the best crewmembers for Luffy's sake, for him to become the Pirate King.
We're seeing all these groups like the Scabbards being torn apart by time, and torture, seeing their devotion tested to such lengths. This even extends to other WG crews like Hawkins, who cares not for his subordinates and sees them as disposable, Law, who's crew failed to live up to their captain, and now Kid's is falling apart, as he tries desperately to bring them together.
Doing right by your lord, trusting your lord, giving back to your lord.
And to think, the timeskip began under the backdrop of the Strawhats training for eachothers sake, specifically Luffy's. Then the first major saga of the New World connects back to this arc, and all the aforementioned themes and messages. Oda has been playing the long game with this. I'm honestly impressed. If the rest of the flashback chapters are this resonate, we're in for something truly special.