Lets start with an overview of the stages of learning. There are 4 of them and they are below. Along with each, I have added brief laymen descriptions and accompanying photos of Luffy chronologically advancing through each of these stages. We have seen this learning process put into use by Oda with Luffy learning all 3 types of haki. Observation, Armament, and Conquers’s Haki. Briefly, recall Luffy learning Armament and only being able to use correctly it only about 50% of the time. Unconscious Incompetence - You don't know what you don't know… Not even aware something exists or is even possible. Conscious Incompetence - You are made aware of something that you did, but you don't know how you did it. (with Kujua, Impel Down, Marine Ford all before receiving training.) Conscious Competence - You are aware of it and can even do it, but you have to focus deeply to pull it off and it is still not done 100% accurately, but you can tell when you made a mistake. You can be very proficient here and even considered slight mastery. This is where a lot of people end up because there are so many levels and you can become overconfident with slight success and slip back into level 2… (two instances at Fishman Island, Punk Hazard, twice at Dressrosa) Unconscious Competence - This is a level of mastery. You don’t even have to think about it, you just do perfectly unconsciously. And now we are here!! With this as my supporting evidence, I want to prove and discuss the following: Luffy is indeed headed towards mastery, this mastery is what allows the Yonkou to be “impenetrable”, that the current Yonkou are each masters of different or multiple types, and mastering all types is what will set Luffy apart as the Pirate King. Shanks - Observation. To be quite honest, what I know about Shanks is mostly from the senior and skilled members/theorists here. I know that his Conquerors’s haki is off the charts, but at the same time he may possess an incredible observation haki that allows him to see really far into the future, or that may even allow him to freeze time for an instant. He’s always cool and calm which are the prerequisites for observation haki as explained to us by Rayleigh, Enel, Katakuri, and Luffy himself. So, if I had to choose one besides Conquerors, this is definitely it. Also, I am aware that we have not seen him be impenetrable, but with the respect he gets from Kaido and Big Mom, there has to be a reason for it. Think about Katakuri, his observation didn’t make him impenetrable, just unhittable!! His will? Similar to Luffy’s is what I would guess. Freedom and the protection of his friends. Big Mom - Conquerors. For Big Mom, this is a power that seems to have manifested naturally as a child. A child prodigy, if you will. Her will for sweets was indomitable as there was literally nothing that could get in her way when she set her mind to getting what she desired. How does this allow her to be impenetrable? Ever heard of Mind over Matter? Unbreakable Spirit? Or, having an Iron Will? The power of the mind is something that all of us as humans are really starting to understand more and more as time goes on. It is said, that nothing can stop the person that knows what it is they want from life and that are willing to do whatever it takes to accomplish it. You manifest your thoughts into reality if you have the patience, determination, and persistence! This is Big Mom personified. Think about how Bege and Sanji described her after meeting her. An impenetrable IRON ball… Tempering your will. Tempering is what they do to steel and iron? She has a temper. Opposite of Shanks. Think about this, the only time she was injured was when her mindset was broken due to the photo of her mom being dropped! What about the significance of her two wills? Well, when the photo was broken at the tea party, her mentality was broken right? So, why didn't the rocket penetrate? Her other will was activated, the wedding cake was destroyed, her dreams of the Germa army becoming hers and creating a place for all races were all jeopardized and her conqueror’s haki kicked in and protected her. Kaido - Armament along with Conqueror’s. The man that can’t be killed. The immortal. Guillotines break on his neck, and spears on his stomach… But, look closely! Maybe, just maybe this is even being activated subconsciously! Another form of unconscious competence! Something that even he can’t control. Maybe even unknown to him as he can not deactivate it to allow himself to die. As we know, all forms of haki are WILL, so Kaido’s armament won’t allow him to die until he accomplishes or fulfills his dream of total destruction on a massive scale… The Drunken master. Will learn more about this guy as the story progresses. But, no doubt in my mind that it will align. Blackbeard - Unknown but definitely not armament… Why not armament? Because he continues to feel pain. And, actually, I believe that he is just a mastermind… Maybe a dark manifestation of Observation and Conqueror’s haki. The way he plots and plans and tries to sneak around actually doing the hard work makes me think that he’s lacking mastery necessary to be king. Very intelligently and meticulously adding the strongest crew members and has the bravado to convince them to join him. Totally different from how Luffy built his. Killing intent vs looking for good hearted people. Power hungry versus Freedom seeking. Now, if he did have only one, I would have to say he is probably closer to Conquerors even though this would contradict the fact that Big Mom is impenetrable. Unless of course, it comes down to different manifestations again… He has the top offensive and top defensive devil fruits to go along with a sharp mind which allow him to remain on top and able to compete with the Yonko, even if he really is lacking mastery. As I mentioned, you can still be extremely proficient and skilled and not be a complete master. Maybe that is what White Beard saw in, or “NOT” in him as in what he was lacking when he assessed him at Marine ford. Now, as we have seen with Luffy, he is beginning to be able to use his conqueror’s unconsciously, also he is mastering observation with his ability to see the future. Luffy mastering all will be what separates him as the King. Just like with his fight with Katakuri, Luffy will have to face and takedown each of the Yonkou and during their fights, he will have to match or surpass them during battle. What was really surprising to me was the way and level of ease Kaido was able to defeat Luffy. I mean, since the beginning of the story, Luffy was known to have monstrous strength, but after each battle he barely survived, he got pushed even harder with physically stronger opponents. Then, he faces a guy that is propped up as THE PINNACLE of undefeated excellence. I figure that the Yonkou must have clashed at one point in time, so being undefeated is nearing the peak of strength automatically. However, the strong always face the strong, so Katakuri never faced a Yonkou. This left us questioning just how much of a difference in strength between a Yonkou and second in command could there be, if any? Well, this was definitively answered with Kaido’s one shot KO of Luffy. Unlike with Zoro, we never see Luffy physically training. But, after training with Rayleigh, he was able to use armament and be still be somewhat powerful in the sea. The very same sea that used to weaken him completely. Now, he literally has sea prism cuffs and is tasked with lifting heavy stones while doing all out sprints… After this, the natural phenom will without a doubt be a WHOLE LOT stronger. And, at this level of what’s upcoming, it’s the phyiscal armament that and power that will be mastered and necessary to defeat Kaido. UPDATE: with this latest manga chapter released, it is becoming more and more clear that Luffy's physical appearance is beginning to change. It is like Doffy said. "you sure are fast, but are lacking heaviness!" Lets discuss!