ONE PIECE GOLDI’m going to start off on a bit of a tangent. Has anyone ever wondered why the technology to feed Devil Fruits to inanimate objects was created? In pretty much every instance it would be more beneficial for one to eat a fruit themselves, unless they already had one and would die. I believe DF powered weapons were merely a side result of another project
The Gorosei ordered Vegapunk to perform a very specific task – The artificial recombination of Devil Fruits. For what purpose? To recreate the fruit of life
So how does this relate to Sanji? Many people have connected the spiral pattern in his eyebrows with those found on all Devil Fruits, but what is his connection with them specifically? He is one. Or more accurately, he is two. In his attempts to recombine the fruits, Vegapunk fed a human human fruit model to another Devil Fruit, which resulted in it coming to life
It is reasonable to assume that the feeding of DFs to inanimate objects is a recent technology as it’s still relatively unknown that it even exists. It’s invention likely coincides with the year of Sanji’s “birth”
As to how Sanji escaped, he was probably given away by Vegapunk himself. Vegapunk is, unlike his masters, not a heartless monster, and decided that Sanji should lead a proper life in the real world. He was sent to North Blue
The reason that he is wanted “only alive” is that the Gorosei have deemed him their “property”, and intend to use his body to further research the possibility of recreating the fruit of life. His identity was determined purely through the now complete spiral pattern from both wanted posters, as there is no way the Gorosei or Tenryuubito could recognise someone who was lost to them as a baby from their general facial features
(This one is COMPLETELY crazy but I feel like there isn’t much variety in Sanji theories at the moment)
*Theory by Go D. Usopp