Hello once more guys.You can probably guess as much by the title,but this theory will involve several concepts so it'll will be quite big and involve a fair bit of reading.Well,that's no surprise though,some may even have prepared themselves for a bit of reading after they saw the name Yuuzume under the title of the theory.Well,I'll cut the small talk here and go ahead with the theory. -What are Devil Fruits? "Devil Fruits are mystical fruits that are found throughout the One Piece world and grant the one who eats them special abilities while also making them vulnerable to sea water" *closes book* *throws book away*. Are we satisfied with that explanation? No,we're not.But Vegapunk is still sitting in Navy research lab building and improving Pacifistas so let's try to come to a conclusion on our own.So,as we all know,when a person eats a devil fruit,they are then referred to as a (name of the fruit)-man.That suggests that the devil fruit doesn't simply grant an ability to it user,it reforms their body down to the molecular level into a body with a completely new set of abilities.That means that to Ace's body,having the properties of fire is normal and the user doesn't feel inconvenient using their powers since they have become "normal" for them.Think about this for a second,we know what abilities each fruit gives because there have been people who have eaten the same fruits before and now there's even an encyclopedia for them.But what about the first time that a person consumed them? How did they know which fruit they ate? They knew it naturally,by instinct.They knew it because it became something normal for them.Like everyone of us knows that we move our legs so that we can walk,or that we can move our arms to pick something up,devil fruit users innately know the abilities they get.I ask you to recall the time when Kaku and Califa ate their devil fruits.At first they said they didn't feel different but Lucci said that they would know their abilities in due time. Spoiler: Kaku and Kalifa And after a while,they each knew what abilities they had gotten without anyone telling them. Now then,I said that devil fruits alter the user's body down to the molecular level.But how exactly do they do that? The answer is that devil fruit change the genetic makeup of a person,in other words they change their DNA itself.Is that possible? Of course it is.Let's look at how DNA is structured.Most people are probably imagining a picture similar to this: Spoiler: DNA 1 but I want you to picture an image like this: Spoiler: DNA 2 because when I say that devil fruits change the DNA structure of a person,I didn't mean that they change the form of the strand itself.What they change are the nucleotide monomers.Yeah,I can hear you,"What are nucleotide monomers?". If you already know feel free to skip this part but if you don't I'll try to explain it properly.The short answer would the colorful pieces in the picture above that are represented by the letters A,C,T,G. But that isn't really an explanation so let's take it from the top. DNA molecules are what we call polymers.So,those polymers are basically a sequence of monomers.Oh man,I sound like my high school Biology teacher,that's a bad sign,it probably means you've already started yawning.Forget all those fancy words.Imagine that Polymers are sentences.If polymers are sentences,then monomers are the individual words that form those sentences.So DNA is basically a series of sentences,it's a text.And the only letters in that text are A,C,T and G which probably do remind you of high school Biology.Now,as far as biology goes,we could go further but that's far enough to understand this theory. So,with your renewed understanding of the DNA structure,I can now tell you that I personally believe that devil fruits change the "words" (the monomers) of the DNA.They replace them with new letters that can't even be found in a normal DNA.For convenience's sake,we can say that they add a D letter in the DNA.Each devil fruit changes the DNA in its own way,its own text.Is that possible? And now you may be thinking "So what?". What does that even accomplish? DNA is what holds the information that the cells need to make proteins.So with new information,the structure and function of the proteins produced by the cells of a devil fruit user differs from that of a normal person.Proteins are the working force of our body,they do all the jobs needed inside the body.So,the proteins produced inside a devil fruit user can do many more things than the ones produced in a normal human. So,now that we said all this stuff,what does it mean in the end to eat a devil fruit? Let me put it simply.Eating a devil fruit is like,erasing your computer's operating system software,then putting in a CD (or any other storage device) and installing a different OS.Eating a devil fruit is nothing more than erasing Windows 8 from your computer and then installing Windows 10.There's no magic involved. -Now,let's talk about another reason why devil fruits are associated with genetics.That reason is the existence of smiles.Smiles are artificially created devil fruits,as we all know.But what exactly does "artificial" mean in this case? How are smiles made? Smiles are made by growing the fruit with the aid of S.A.D. What happens is that the DNA of the fruit is altered while it's growing,to a DNA similar to that of a devil fruit.Can a fruit's DNA be altered? Of course,it happens in real life aswell.One way to accomplish that is by a process called Chemical Mutagenesis.It's basically a process where chemicals are used over a certain time span to slowly alter the DNA of the fruits,in this case that chemical is the S.A.D. However,as one can imagine,the chemical used for such a process can be quite dangerous to humans.That's why Law said that eating artificial devil fruits has risks.(That's from chapter 698 for anyone interested.) Spoiler: Law I mean,if we think about it,the one who came up with S.A.D isn't Caesar,it's Vegapunk.So why is Kaido the one with the army of devil fruit users and not the Navy? That's probably because Vegapunk understood that the artificial devil fruits would cause harm to the ones who ate them so he shut the project down.This is how the Gifters and Pleasures from Kaido's army actually ended up looking. Spoiler: Gifters Spoiler: Pleasures We can distinguish the Gifters thanks to their two black horns and the pleasures thanks to their single white horn.That's a possible genetic mutation that occurred from Caesar using chemicals to create artificial devil fruits,chemicals that cause unwanted alterations in the DNA of the smiley devil fruit users in the form of mutations,at least. Now,maybe you thought this is the end.Sorry,but no.There are still concept that need to be explored when devil fruits are concerned. -Why are devil fruit users vulnerable to sea water? Why would a change in DNA cause people to become vulnerable to sea water? The answer is because water weakens the bonds that hold the DNA together.Take a look at the picture I showed you before. Spoiler: DNA 2 As you can see,DNA consists of two strands and each strand has its own set or pieces/blocks that connects with their corresponding counterparts of the other strand.But how are those pieces connected with each other so that the DNA becomes stable? The answer is not glue.It's hydrogen bonds.A hydrogen bond is the bond that connects the hydrogen atoms on the one stand of DNA to the oxygen atoms on the other.What you need to know about this kind of bond,is that it's weak.There are a couple of reasons why such bonds can stabilize the DNA despite being weak.First of all,there are a lot of them.Secondly,they have hydrophobic properties.That means that they don't allow the surrounding water to get near them.That is why the hydrogen bonds are not weakened even though the body of a normal person contains a big percentage (60-70 %on average) of water.So the end result is that the DNA is surrounded by water on the outside but doesn't let water weaken the hydrogen bonds that are on the inside part of the strands.Basically something like this. Spoiler: DNA 3 And lastly,the bond between the monomer pairs (A-T,C-G) also helps in stabilizing the DNA,especially the bond between C and G.This is a bit relevant too but our focus will be the hydrogen bonds.The main thing to remember about the hydrogen bonds is that they can be weakened by water. We've established that devil fruits change the monomers of the DNA.So the monomers become different from the ones we are familiar with.So we can't say that the strength of the bonds between the new pairs of monomers is the same as before.Also,we don't know the properties of those new monomers.So we also can't assume that they possess hydrophobic properties which help keep the water away.But we do know that devil fruit users get weakened by water so we can make the following assumption."The strength of the bonds between the new pairs of monomers is NOT as strong as before." Just from that the DNA becomes less stable.But there's also this assumption."The new monomers either don't have hydrophobic properties or it has become less powerful" Now the DNA becomes even less stable just from the water inside the human body.However,even though it has become less stable,it's still not a problem.But what happens when you include water from external sources as well? That's when the DNA structure starts to destabilize and begins to unfold,like this: Spoiler: DNA 4 We're talking about the hydrogen bonds of DNA breaking down,something that happens to this extend usually after the death an organism.Devil fruit users essentially come one or two steps before the the state of death itself.They come at the point where the DNA is not completely destabilized but its bonds have been damaged enough to cause its functions to come into disarray.Hence why they seem to get weaker at the very touch of water and why they become completely immobile underwater. However,here's the 500 million beri question.Why sea water and not purified,drinkable water.That's because purifies water has had the microorganisms,DNase,RNase,salts and all the other impurities that can further damage the DNA removed.In simpler terms,sea water can cause enough harm to the DNA of a DF user to trigger the reaction I mention above,while purified water can't cause enough damage to destabilize it. -Now,since we have bothered to learn all this stuff about DNA,let's try to implement them to one more concept,shall we? Let's try to explain why Blackbeard was able to obtain 2 devil fruit abilities. We have established that devil fruits alter the DNA of a person.But what happens if a person has two different sequences in his genetic code? You've guessed right,they could consume 2 different devil fruits without a problem. Spoiler: DNA 5 In the first place,why is eating two devil fruits normally impossible? Because that would be like installing two different operating systems in one hard drive (without partitioning the hard drive).Simply put,it's what you would do if you hate your computer and yourself.But we're not talking about computers here (they're more important),we've talking about the very body of the user.There would two different sequences in the same DNA.The information would be messed up and the proteins produced with such information would be messed up as well,the body would lose its functions and begin to go haywire.In the end,the conclusion would be what we all know,death.But since each devil fruit can only alter one DNA sequence,a person with two of them could eat two of them without a problem.That would be like installing two OS in the same hard drive (while partitioning the hard drive). So how does Blackbeard have two different sequences of DNA? Is it possible that Blackbeard has a fraternal twin? To that question,we all say to Oda "No,thank you". One weasel (who also killed Ace) is enough at it is.Sometimes,when one out of two fraternal twins dies before it's born,the other sibling absorbs the cells.So did that happen with Blackbeard?It's a bit morbid so let's hope it didn't.And we're left with one other option.Sometimes a baby can absorb the cells of its mother before it is born.The reverse is also possible but our focus right now is Blackbeard.So,we know Blackbeard carries the secret name of D,so his mother also did.Now,can you recall another mother with the name of D that did something astounding during her pregnancy? That's right,Portgas D Rouge.So Blackbeard presumably absorbed some of his mother's DNA,which effectively made him a genetic chimera.Not this one. Spoiler: Chimera 1 This one. Spoiler: Chimera 2 Now we know why Blackbeard can have two devil fruit abilities at the same time.But wait a minute,Blackbeard didn't eat a second fruit,he stole Blackbeard's abilities.How is that possible? The answer is the power of the Yami Yami no mi.Teach can suck anything out of a person,including a person's DNA cells.That's right,he stole the genetic sequence of Whitebeard's already altered DNA and used it to alter his own second one.But then why did he have to wait until Whitebeard was dead? Well,besides the fact that he would get wrecked if he tried to steal it while Whitebeard was alive,there's another reason as well.While the person is alive,the hydrogen bonds that stabilize the DNA structure are active,and Blackbeard's power isn't enough to to simply steal it while a person is alive.But it's enough to destabilize it to the same point that sea water also does,thus effectively nullifying a devil fruit user's abilities.So what changed when Whitebeard died? The same thing that happens when all organisms die,the bonds that bind the cells and the cells themselves begin to deteriorate and die out. However,there still remains one question.Why did Blackbeard throw a black sheet over Whitebeard before stealing his powers? The main reason is because he's the ultimate example of an attention whore (pardon the vocabulary) in the One Piece world.And we're talking about a world where people shout out the names of their attacks,so he must really love attention.The second more minor reason was to block the UV rays of the sun.Normally the cells disperse the radiation of the UV light as heat and protect themselves from getting harmed.But Whitebeard was dead,his cells were dying and were deteriorating as time went by.If the DNA cells were damaged too much,Blackbeard wouldn't be able to steal the DNA sequence.Black color offers the best protection against UV rays overall the other colors because it lets the least amount of light to pass through. Spoiler: Black Color Or rather,the reason why our eyes see an object as black,is because it absorbs the light that falls on it o it doesn't reflect any of it towards our eyes.So what was the best way to keep Whitebeard's DNA from being damaged while keeping the process a secret so that no one knew anything about it? The answer is what we saw in the anime and what you can see in this picture. Spoiler: Blackbeard This concludes the theory.I know it was boring to read so much but I hope the content was worth the read.This theory was a bit unusual for me because I normally prefer it for more evidence to show up and then make a theory.But with Vegapunk's appearance approaching,I thought I'd put this out there for what it's worth.Thank you for reading,this was a theory made by Yuuzume.