So during the fight with Kaido, when Luffy unlocked Gear 5, he believed that he finally had hit his peak. Now this obviously doesn’t mean that there still isn’t some room left for him to grow, as he does need to fully be able to utilize his abilities to the maximum potential.
However, this is in reference to “Gear 5” being the highest form that he will achieve. From a surface level, this does seem to be the case. He’s had his Awakening, and finally achieved what he believes is his final Gear. There is a key phrase in all of this though. That is “What he believes”……
There was something interesting I noticed when reading Road to Laugh Tale Volume 3. The headline read “Luffy’s Peak, the ability to turn imagination, into reality.” However, right underneath is what was interesting…. “Luffy was convinced that he had finally reached the Peak of his abilities when he discovered his “Nika” form….”
You see where I am going with this? Right now, Luffy is convinced that he has reached his peak. That’s where his mindset is at. We all know that Luffy’s fighting style has always revolved around using his imagination. So what happens if Luffy comes across a foe (which he will) by the End of Series, that his current self can not beat? The Nika fruit grants him the ability to turn imagination into reality. He will be forced to re-evaluate his own strength, and try to achieve new heights. That is where his final “form”, or rather his “peak” will finally be achieved. That is where I believe Oda is going with this. Luffy ain’t done. Right now he’s capped due to his own belief, but in the near future, he will break past that cap, because he will be forced to do so, by a force that he can not overcome in his current state.
*by Celestial D. Dragon