The heartbreak that the reader is feeling during this chapter and the following ones, where the tension is palpable, is rendered for a reason: we are meant to believe that Usopp is gone and that the crew will not survive that event.
This event, compared to those of the failed Joy Boys or the following hardships, is quite different, as it does not directly involve any of the three pillars of power in the world, but is a very intimate moment for the crew.
This fight, and the departure that ensued was entirely due to something emotionally deeper than simply the crew being overpowered.
However, it may be interesting to say that the first big sign that Usopp was losing his faith in his own strength could be seen in the panic fight against Admiral Aokiji, in Long Ring Long Land.
Thus, in a way, one of the three pillars was responsible for the crew crumbling in Water Seven and, quite surprisingly, the World Government and the Marines patched them all back together, by representing a power to overcome in order to save a friend.
- The loss of the crew in Sabaody
This moment, which I believe to be one of the most tragic events in the series in the reader’s eyes, represents the pivotal moment when Luffy could have lost himself.
At this moment, when the whole crew disappears, Luffy crumbles entirely.
What information does it give us?
It indicates that the crew and the attachment to them are defining elements to keeping one’s dreams alive.
As it has been shown with the failed Joy Boys, a common denominator for all of them seems to be the loss of their crew, or at least of the loyalty and trust of their crew, in the case of the earlier opponents.
In this moment, the Straw Hats were virtually annihilated, and would truly have been if not for the intervention of Bartholomew Kuma.
Thus, the crew have almost been defeated by the Marines, but saved by a Warlord of the Sea. Luffy specifically would then be helped and saved several times by a second Warlord, this one being Boa Hancock.
This creates a disruption in the pattern that would point to the fact that Luffy is “The One”: the pillars are finding a disagreement in his treatment.
- Ace’s death
For Luffy, this event marks the moment that he has truly reached the pits of despair, and that feeling is well conveyed to the reader, as our protagonist completely shuts down and stays in a state between life and death for several days afterwards.
It comes to a point where Luffy is on the verge of abandoning his dream -meaning that he is losing sight of his hope, and is losing his possible Joy Boy title.
Luffy, after Ace’s death, is in a state of complete shutdown and tetany, being unable to think further than the cloud of grief that has veiled his mind.
This, however, is where his reaction to the trial is interesting, compared to the failed Joy Boys.
He stands back up.
How does he do it? Thanks to Jinbe, and thanks to his friends, still there with them in spirit, and trying their best to get out of their islands.
He sends a signal to avoid going into such a massive wall again, by taking a step back for two years in order to get better prepared for the New World.
This makes him a good contender as Joy Boy. This is the reason why it works: his dreams have known the risk of being shattered, and yet they are coming back more powerful than ever.
Here again, Luffy’s will was almost destroyed by the Marines, but he was saved by many Warlords -former, current and future ones: Crocodile, Jinbe, Trafalgar Law, Buggy, Boa Hancock. Added to that, we could argue that the third power, that of the Emperors of the Sea, also showed to break the pattern, as two Emperors -Whitebeard and Shanks- showed their support to him in a way or another during the war.
