The Secret to Big Mom’s Size, Strength and Vulnerability


I’ll get straight to the point. I think Katakuri’s/Rayleigh’s explanation of haki was the final piece to the puzzle that is Big Mom’s vulnerability. Though she’s demonstrated monstrous feats (from giving life to a candy tsunami to tanking a Coup de Burst to the face) some of us were left scratching our heads during her moment of weakness upon seeing Mother Carmel’s broken picture. How could her emotions make her weaker? How could someone capable of being unphased by so much damage be vulnerable to simply scraping their leg…well, now I think we know.


Concentration is not only necessary for observation haki, but for ALL HAKI. Let’s break it down.

We’ll start by trying to pin down what exactly haki is. As Raleigh has stated, haki is something that resides in all living things, though few ever come to control + realize that power. However, it’s also been called “willpower.” To complicate this further, Raleigh says, “’The act of not doubting.’ That is ‘strength!!!’” He goes even further to say it’s, “presence, fighting spirit, + intimidation,” no different from the things that humans can naturally sense. We also now have to complicate this further w/ the fact that becoming flustered can prevent one from using their observation haki effectively….

Here’s my interpretation. Though maybe Oda has something even greater planned for a later reveal, I personally find my idea to be pretty bulletproof. It takes from a few different theories I have, but it does seem to fit all the pieces together w/out being an… “asspull.”

Ignoring all the various names for now, I presume haki to fundamentally be life energy (chi, ki, energy, mana, life force, etc. in other series…call it what you want). As Rayleigh states, it’s a power that lies dormant in all living creatures. So yeah, a power that resides in living things, I think I’d call that life energy (or any other synonym for it). So, all living things have this power, this energy, + they just can’t access it. Either they don’t know it’s even there or they can’t seem to activate it. Now we can start considering the other various names. Let’s start w/ willpower.

How can it mean both life energy + willpower?

It is b/c you must enact your will upon your own power! So technically, haki speaks more to how one actively commands his or her own internal power. So while we sometimes seem to use it to refer to the actual reserves of spiritual/life energy a person has, it actually seems to speak more to ability to wield/manipulate that stored energy. If you have all this pent up energy, but you can’t get yourself to use it, it’s wasted.

How does the presence, fighting spirit, + intimidation come into play?

As we can see w/ how we defined it earlier, it’s the manipulation of this life energy. The three different applications of this manipulation are what give us “presence, fighting spirit, + intimidation.” 

Here’s the list:
1) Presence: This is allows one to sense the presence of others, as the name suggests. In short, it’s observation haki.


2) Fighting spirit: This literally means fighting w/ your spirit. Or alternatively, a spirit for fighting. Applications of this include covering yourself w/ an armor of internal energy as well as projecting it outward in the form of a shockwave. So, we recognize this display as armament haki.


3) Intimidation: This form occurs when trying to dominate another’s will/life energy w/ your own. It of course is the King’s or Conqueror’s haki that we’re all familiar with.

Back to willpower, if this interpretation of haki is accurate, it also makes sense of a Blackbeard’s comment to Luffy in Impel Down. He tells Luffy that his haki has grown stronger since they last saw each other. While yes, Luffy had displayed Conqueror’s haki three times (though all unintentionally) since there last encounter, Blackbeard shouldn’t be aware of it. Additionally, Luffy didn’t show any haki capabilities when they first met, so it seems odd to say his haki has grown stronger. If anything, you’d expect him to say something like, “So you’ve finally awakened your haki, Zehahahaha!” In addition to saying that Luffy had gotten stronger, he also said his haki had gotten stronger “too.” This suggests to me that haki specifically refers to the mental strength AKA will of the person, not their abilities.

So what’s different then? What has happened to Luffy since they last met?

Luffy has constantly put himself against every big bad he’s been able to find, constanly putting his life in danger. Oddly enough, Rayleigh told Luffy something interesting that justifies this. We now know that putting yourself against hard opponents makes your haki blossom. In other words, putting your life in danger improves your haki.

So how does that make sense w/ your interpretation of haki??

It’s b/c you’re life in on the line, just like Rayleigh said. In those moments, you don’t just get some nakama power up. You don’t pull ability out of thin air, + your body is no different than it was moments ago. What has changed is you WILL! By risking death, you increase your will to live. This increased mental fortitude is what let’s you do what you need to do to survive. It’s either sink or swim, + your will to survive forces you to take command of your body (specifically your life energy).

I also think people misunderstand Rayleigh’s quote, thinking that something magical happens when you throw yourself into battle. The fight isn’t so important as much as the stress + severity of the situation that counts. Just think back to pre-timeskip One Piece. Luffy managed to use his King’s Haki to both save both Ace + Marguerite from death. Luffy’s back was to a wall, but his WILL to save them forced his body to take command of it’s own dormant abilities. The same occurred for Coby, who was not himself actually part of significant fights (gonna ignore that excuse of a try against Luffy lol) that awakened his haki. Instead, it was his want/will to stop all the unneecessary deaths that caused it. Basically, traumatic situations increase your will to live/change circumstances (not exclusively fights). We can also look at another description…

“The act of not doubting. That is strength!!!”

Why would Rayleigh mention doubt, + how does this relate to his haki lesson? I think the word “act” speaks loudly to this point. It is not power alone that makes one strong. Instead, it is the will to act that makes one strong. One can have all the power in the world, but if they don’t have the will to take action, it’s useless. Again, this speaks to one’s mental strength. In those moments where death is likely, you have no time to doubt, and having no doubt is strength.

So, that just leaves one more description of haki to make sense of…

Katakuri said that he needs to focus in order to use his observation haki. While you might be tempted to assume this is unique to observation, I don’t. This focus, again, refers to your mental state. You need composure to utilize your life energy…and I think this is what explains Big Mom’s brief moment of vulnerability.

If you have read my other theory, you know that I suspect Big Mom is a former child of giantification. As Chopper said, those children are bound to experience their bodies degrade over time, ultimately dying in the process.

So if that’s the case, shouldn’t Big Mom be dead??

No. Who in the entire One Piece-verse has the unique ability to assemble vast amounts of life/life energy? BIG MOM! B/c of her absurd reserves of life energy, she is capable of putting out constant haki, a feat only possible for a person w/ her devil fruit. It’s also possible that every person puts out a baseline amount of life energy, + this is what observation users are able to take advantage of, sensing the location of their life force (though this wouldn’t account for willpower/mental focus).

This ability + her being an artificial giant + this haki interpretation also explains why she scrapped her leg. Her body is degrading/degraded. Even though her body is actually somewhat fragile, she has the unique luck of bypassing the ailment w/ her life (+ therefore haki) ability. She essentially has a non-stop force field protecting her weakened body. Additionally, we’ve even seen Big Mom’s body continue to degrade as she’s rampaged constantly. The reason her body didn’t degrade as a child while destroying the giant’s village is that her body had not yet started degrading. This is just like the children of Punk Hazard, who appeared fine (despite Chopper’s warnings).

The most compelling evidence is the catalyst for her vulnerable moment, the breaking of Mother Carmel’s photo. In that moment, Big Mom lost all composure. Just like Katakuri, she was unable to utilize her haki abilities. While she still has the body of a giant + is therefore still capable of great physical strength, her defenses are weak + weakening. I personally feel that most people have completely forgotten that Big Mom’s secret vulnerability, the primary thing that caused Luffy to team up w/ Capone in the first place. Whatever happens, I’m excited for what Oda + Big Mom have to reveal to us.

*Theory by TwinKidd_B

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