Okay, now I don't have nearly as much evidence as I'd want before writing a theory, but since the Vinsmokes are pretty new to the story, there's not a lot available. There is a decent amount of ass-pulling because of this, so I apologise in advance.
Also, if you haven't read the manga up to the last chapter, there will be SPOILERS ahead since most of my evidence is coming from Chapters 826 and 828 (I'm putting it in huge, bold text so nobody can miss it and be all "dam marco u spoil me... -1")
First things first, let's look at Pekoms' description of Germa 66:
We saw those weird shoe thingys that Yonji and Reiju were wearing that allowed them to float in mid-air; those are quite far ahead of their time. We could also hazard a guess that they have advanced weapons, and that Big Mom wants to make use of them.
But does their technology stop at weapons? Is that all Big Mom is after? This theory says "No". If Big Mom wanted weapons, we would expect to see a stronger connection between her and the underworld, namely Doflamingo. But, we didn't see any such connections during the 100-chapter epic that was the Dressrosa arc. So, perhaps she's after something else... But what could it be?
Go back to Chapter 793 for a second: Capone, who is under Big Mom's umbrella, is going after Caesar Clown, presumably for Big Mom (the attachment for the panel wasn't working so I have no picture here, sry)
Caesar Clown's area of research as a scientist was artificial Devil Fruits, a field that only two scientists in the One Piece universe (that we know of) are looking into: Ceasar Clown and Vegapunk.
Vegapunk is a man who has been described as being "500 years ahead of his time", and is the man who worked out the mechanisms behind Devil Fruits.
However, Vegapunk is not the only scientist privy to this information; Caesar, at the very least is, and I would say that any of his collaborators would be as well.
"But Marco what's this got to do with Germa why are you still writing words just stop PLS"
I can't stop, I won't stop.
So far in this theory, I've mentioned a technologically advanced fighting squad and a technologically advanced scientist. Now, at the risk of sounding like a complete and utter ****, I'm going to assume that technologically advanced weapons require technologically advanced scientists to build them. And this is where the connection between the Vinsmokes and Vegapunk's research, or even Vegapunk himself, is made.
Whether it turns out that Vegapunk once worked with Germa scientists before he joined the Marines, or whether the Vinsmokes have access to him through their World Government based connections, it's highly likely that Germa 66 have used his research on Devil Fruit lineage factors on some of their own fighters. Ironically, this will contradict another theory I've written, but dammit I've spent far too long writing this to delete it all and say "never mind" now.
Cast your minds back to Chapter 826, and Reiju's poison ability:
The first assumption we all made was "Butterfly DF". But what this theory is now going to say is no, it's not a Butterfly DF. I believe that Reiju's ability could be a result of manipulating her "lineage factors" in a way similar to how a Devil Fruit would, but without eating a Devil Fruit, and thus (presumably) eradicating the gnarly side effect of not being able to swim.
Let's look at Ichiji, or as he's currently known in the manga, "1"
Again, this ability would appear to be a Devil Fruit ability at first glance. It looks like one, and there's no other real explanation for it, so it's the most logical conclusion. But again, like Reiju, Monsieur 1 over here is a result of that same lineage factor manipulation
In order to fully justify this theory, I'm now going to contradict one of my own theories (which may or may not say something about the impulsiveness of my theory writing).
Let's look at Diable Jambe:
If Sanji were introduced to the story, and if he were using this ability from the start without prior explanation as to what it was, the most logical conclusion would be... Devil Fruit. But, we know that it isn't a Devil Fruit ability. There's no "natural" way of explaining how this ability works without it. Sanji, being a Vinsmoke, has a connection with the Germa 66 army. So it wouldn't be unreasonable to assume he was "given" this ability at a young age.
I could stretch things even further and say that the reason he didn't use it until Enies Lobby was because this ability is a reminder of his past with Germa, and the ties he severed with his father. But, the necessity to become stronger and overcome more powerful enemies forced his hand, and meant he had to use it. The fact that he barely used it was what caused him to have to spin around a bit to activate it, but through his training in the timeskip, he was able to learn how to fully control his abilities.
If he ever got a Germa code name, I would imagine that it'd connect to his flames or something like that, since "Black Leg" is an epithet that relates to the martial art style he uses.
Now, bringing this back to Big Mom. Thanks to her information obtaining network, mentioned by Pekoms in chapter 815, she knows the true extent of Germa's technology, including their ability to "create" Devil Fruit abilities, and wants to make use of this to strengthen her own crew. And her way of doing this is, as we know, having Purin and Sanji marry to tie the two families together.
Your thoughts?
Also, if you haven't read the manga up to the last chapter, there will be SPOILERS ahead since most of my evidence is coming from Chapters 826 and 828 (I'm putting it in huge, bold text so nobody can miss it and be all "dam marco u spoil me... -1")
First things first, let's look at Pekoms' description of Germa 66:
You must be registered for see images
We saw those weird shoe thingys that Yonji and Reiju were wearing that allowed them to float in mid-air; those are quite far ahead of their time. We could also hazard a guess that they have advanced weapons, and that Big Mom wants to make use of them.
But does their technology stop at weapons? Is that all Big Mom is after? This theory says "No". If Big Mom wanted weapons, we would expect to see a stronger connection between her and the underworld, namely Doflamingo. But, we didn't see any such connections during the 100-chapter epic that was the Dressrosa arc. So, perhaps she's after something else... But what could it be?
Go back to Chapter 793 for a second: Capone, who is under Big Mom's umbrella, is going after Caesar Clown, presumably for Big Mom (the attachment for the panel wasn't working so I have no picture here, sry)
Caesar Clown's area of research as a scientist was artificial Devil Fruits, a field that only two scientists in the One Piece universe (that we know of) are looking into: Ceasar Clown and Vegapunk.
Vegapunk is a man who has been described as being "500 years ahead of his time", and is the man who worked out the mechanisms behind Devil Fruits.
However, Vegapunk is not the only scientist privy to this information; Caesar, at the very least is, and I would say that any of his collaborators would be as well.
"But Marco what's this got to do with Germa why are you still writing words just stop PLS"
I can't stop, I won't stop.
So far in this theory, I've mentioned a technologically advanced fighting squad and a technologically advanced scientist. Now, at the risk of sounding like a complete and utter ****, I'm going to assume that technologically advanced weapons require technologically advanced scientists to build them. And this is where the connection between the Vinsmokes and Vegapunk's research, or even Vegapunk himself, is made.
Whether it turns out that Vegapunk once worked with Germa scientists before he joined the Marines, or whether the Vinsmokes have access to him through their World Government based connections, it's highly likely that Germa 66 have used his research on Devil Fruit lineage factors on some of their own fighters. Ironically, this will contradict another theory I've written, but dammit I've spent far too long writing this to delete it all and say "never mind" now.
Cast your minds back to Chapter 826, and Reiju's poison ability:
You must be registered for see images
The first assumption we all made was "Butterfly DF". But what this theory is now going to say is no, it's not a Butterfly DF. I believe that Reiju's ability could be a result of manipulating her "lineage factors" in a way similar to how a Devil Fruit would, but without eating a Devil Fruit, and thus (presumably) eradicating the gnarly side effect of not being able to swim.
Let's look at Ichiji, or as he's currently known in the manga, "1"
You must be registered for see images
Again, this ability would appear to be a Devil Fruit ability at first glance. It looks like one, and there's no other real explanation for it, so it's the most logical conclusion. But again, like Reiju, Monsieur 1 over here is a result of that same lineage factor manipulation
In order to fully justify this theory, I'm now going to contradict one of my own theories (which may or may not say something about the impulsiveness of my theory writing).
Let's look at Diable Jambe:
You must be registered for see images
If Sanji were introduced to the story, and if he were using this ability from the start without prior explanation as to what it was, the most logical conclusion would be... Devil Fruit. But, we know that it isn't a Devil Fruit ability. There's no "natural" way of explaining how this ability works without it. Sanji, being a Vinsmoke, has a connection with the Germa 66 army. So it wouldn't be unreasonable to assume he was "given" this ability at a young age.
I could stretch things even further and say that the reason he didn't use it until Enies Lobby was because this ability is a reminder of his past with Germa, and the ties he severed with his father. But, the necessity to become stronger and overcome more powerful enemies forced his hand, and meant he had to use it. The fact that he barely used it was what caused him to have to spin around a bit to activate it, but through his training in the timeskip, he was able to learn how to fully control his abilities.
If he ever got a Germa code name, I would imagine that it'd connect to his flames or something like that, since "Black Leg" is an epithet that relates to the martial art style he uses.
Now, bringing this back to Big Mom. Thanks to her information obtaining network, mentioned by Pekoms in chapter 815, she knows the true extent of Germa's technology, including their ability to "create" Devil Fruit abilities, and wants to make use of this to strengthen her own crew. And her way of doing this is, as we know, having Purin and Sanji marry to tie the two families together.
Your thoughts?