In One Piece Chapter 1023, Queen told Sanji if those fire legs are a machine, but Sanji told him that he is 100% human. After that, Queen wonders if a normal human can create fire and tells him that if he is not from the Lunaria race.

Also, Marco the Phoenix Stated to King :
“I heard that long time ago, a race of being that can create fire lived on top of the “red wall”. King the Fire?”

The question is: “Is there any connection between Sanji and King? “. All of us knew that Sanji is not a Devil Fruit User. We already know Judge was scientist and what was his capable of. If Judge and King’s Race is related then he should use the fire to melt the candy of Perospero while his whole family are stuck, but they’re saved by Sanji instead, in Whole Cake Island. Thus, King and Judge do not have any relationship.

However, there’s someone completely mystery, and enough to explain everything, she is Sora – the mother of Sanji. Sora and King’s Race Relation is a huge possiblity, because Sora is a character with full of mystery in One Piece World and her son Sanji create fire too without the devil fruits power.

But Why Ichiji, Niji, Yoji and Reiju (Sanji’s Siblings) are not be able to create fire? I think their mind were exposed on scientific technologies, they didn’t train to use fire, and they didn’t know they can create fire. In other words, they can create fire just like Sanji but with more training. However, since they don’t know about it, then they can’t awaken their ability from their mothers bloodline. Luffy’s Red Hawk is out of the line because he is Devil fruit User.

We already know Germa 66 used to travel from North Blue up through red line to East Blue. Here’s the question, so Sora and Judge meet on Red Line and fell in loved to each other? Without knowing her race…