This character has been visited occasionally but has a deeper tie that one day I believe will come up again. Suprisingly this theory does not have many assumptions, just loose connections that don’t seem to have been connected before.
Let’s dive in and explore Kaya’s relationship with the World Government.
To start with we know Kaya live in a mansion in a small village called Syrup. Right there, starting right there we have something unprecedented. There has been no other small island village with a mansion, not to mention, a gated mansion, with suited guards who carry pistols. Now the guards are not much to go on as they were hired by Capt. Kuro to guard Kaya from Usopp, though having enough resources to do that is still significant.
The closest thing we have seen to this since was Arlong’s base which was a previous Marine base.
This is a family that could hire vagabonds off the street without worry, one that cared for the people as doctors/physicians. One that has fiercely loyal staff who we only ever see a small part of. A family that had both the Father and Mother die to an illness and leave their daughter behind with enough wealthy and loyalty from their staff and guards to make sure her future was secured.
This on its own is very rare in One Piece’s world, let’s dive a bit deeper and see what we can find out.
After Usopp left we know that Kaya left the village after getting her strength back and after teaming up with the previous Usopp Pirates she seems to go to another island/town. This one is more developed and is clearly no longer Syrup Village:
https://www.pinterest.com/pin/855402522946984969
The only other cover art updates we get from Kaya are with her studying with suitors trying to get her attention with Merry fending them off and one of her back at Syrup village again getting an updated bounty flyer for Usopp.
With those update there really isn’t much to go on in terms of Kaya, but there is one key figure that tells us a lot more than you would expect. Enter Merry.
From the image below we can see that his stylized horns, hair, and split lip design are not the result of anything other than genetics.
https://static.wikia.nocookie.net/onepiece/images/e/ef/Merry_Young.png/revision/latest/scale-to-width-down/814?cb=20130527010441
Other than Minks, who don’t fit, or devils fruit users we have not seen another human/animal hybrid like him before. That is, until Punk Hazard.
There we meet the Satyrs, previous prisoners who have had their lower halves replaced due to a poison gas. That explains their lower halves, but what about the upper half?
https://static.wikia.nocookie.net/onepiece/images/7/77/Satyrs_at_Punk_Hazard.png/revision/latest/scale-to-width-down/729?cb=20140916074727
In the image above we can clearly see the same kind of white curly hair, ram horns, if a bit larger, and even Caesar himself has the same ram’s horns if not a little longer.
https://onepiece.fandom.com/wiki/Caesar_Clown
With that in mind. The only place we ever see this race is associated with scientists and the world government. Specifically Vegapunk and his research. I would put forward that this race of people is either:
A genetically engineered race/experiment by Vegapunk while learning about the Lineage Factor (DNA)
A race that Vegapunk and the world government has ties to that are very dedicated and intelligent in their field of study.
With this in mind and those two options I do not think it is a stretch to say that one day we may very well see Kaya be met by or at least acknowledged by Vegapunk or other world government physicians as related to their former colleagues. Merry’s position as Kaya’s butler may very well have been a family of this species that Kaya’s parent’s got to know and a young Kaya and Merry got a long even being several years apart in age. Making him a prime candidate to watch over their daughter in the peaceful East Blue.
Let me know what you think of this one and have a good weekend.