I really like the chemistry between Kid and Luffy. This might even be one of my favorite scenes. How strong some characters are without their DF powers is something that always lingers somewhere in the back of your mind and it's also quite hard to keep things in perspective when we follow the story mostly through the adventures of the Strawhats, who are almost always at the front. But seeing Kid and Luffy shackled with seastone being badasses, really shows what kind of entities they have become even without their powers.
It also shows what a 'Conqueror' truly is. It's still a bit unclear what kind of difference it makes in actual combat, but outside that Oda really portrays its status in a very subtle way throughout the series. While people like Bege, Hawkins and Apoo submitted themselves, Kid and Luffy did not, no matter the circumstances. Even if they did it out of pure pragmatism and reason, it somehow feels that the moment they did that, they 'lost', that they disqualified themselves. The Haki of the Conqueror is an irrational force of nature and that is shown quite nicely in this chapter.
Urogue actually defeated a commander but kid couldn't do much.
So the guy above do have a point that how kid is keeping up with luffy(not to forget he doesn't have an arm)
It's not like Luffy learned cheat codes. The point of the time skip was to prepare the Strawhats so that they shouldn't go through the pain Luffy suffered when he lost Ace and story-wise, it's not like much time has passed since the return of the Strawhat crew. In that short timespan though, Luffy accumulated a 1.5b bounty, territory, an armada and tangled with the Yonkou.
Maybe Luffy would have obtained similar results if he went to the NW immediately, though most likely it would have taken much longer and would potentially have cost him dearly. Just look at Kid, one side of his body has been mangled, but he is still alive and going. Meaning he went through extreme hardships the last two years and that means something. So I don't really see any issues here with Kid keeping up with Luffy as it's kind of a superficial way of viewing things.
