Garuda could just be the title for the king of germa. Which means the landless kingdom of germa could’ve been the original kingdom of the lunarian.
Also it would not explain where Sanji's fire powers came from or to better spell it out, how was such modification feasible without possessing a probe of a Lunarian DNA.
Perhaps Sanji is a genetically modified Lunarian and Judge is not but I have less reasons to think of it this way for now.