The Lunarians' kingdom name was...

Okay, this is a small theory that leans a bit hard on Japanese name reading and nomenclature, so please bear with me (also sorry about some of the images' formatting, I don't quite get the hang of this site yet).

I've always wondered about the possible deeper relationship between the winged tribes and the Elbaph giants. This is just the preface of the theory, so allow me to list some of them in quick succession:

1. Enel (and his priests) comes from Birka, and is obsessed with reaching Fairy Vearth, which houses the ancient moon city of the same name. Birka was a Viking Age trading center in what's currently present-day Sweden and former part of Viking Scandinavia.

2. Skypiea houses the Giant Jack, a beanstalk that obviously references the English fairy tale in which a boy finds a giant's house on the clouds.

3. Skypiea also houses giant fauna and flora, not only local but also just plainly bigger versions of Jaya's fauna like the South Birds:

   

4. Random crewmates from Dorry and Brogy's crew know about sky islands like it's basic knowledge for them:

You can also add things like the Astral Realm possibly being at the same height as Skypiea and/or the Red Line, or it tying into High West, which was mentioned by Gan Fall as an alternate route to reach the White White Sea, but for the me biggest smoking gun has always been a very minor thing:

Enel's whole DF repertoire is based on Lightning-related deities and beasts, as Oda himself recognizes in SBS Vol. 33, with Elthor being his most prominent technique and obviously referencing Thor. It is written like this in Japanese:

Katakana: エル･トール (literally pronounced as Eru Tōru)

Kanji: 神の裁き(can be literally read like God's (神) Judgment (裁き) (the の character just expressing possession or a link between two words).

Now, how does Elbaph and the Lunarians factor into all of this? Simple.

We don't have Elbaph's name being written in kanji, just katakana (エルバフ, literally pronounced Erubafu). The name sounds phonetically similar to Elthor, so maybe the kanji reading would follow the same structure and we could have it be God's (神) Something (???). Do we have anything that could fit the bill?

Well, yes, we do:

Whitebeard talks in 1023 about the God's Land (神の国, Kami no Kuni) that was in the Red Line long before Marie Geoise and the WG came to be.

So: could Elbaph's kanji reading be 神の国? Maybe, instead of it being the name of an (Ancient) Giant individual (yes, even possibly the War God Elbaph that Dorry mentions in Little Garden once and then never gets brought up again), it was the original name of the Lunarian Kingdom from whom the Giants took their name after they were eradicated?

There are many avenues about how that possibly came to be: were the Lunarians and Giants allies and the latter took their name as a sign of respect? Or were the Giants the ones responsible for their eradication and thus stole their name as part of the spoils from war? Is this related to Nika being an Elbaphian deity and Lunarians waiting for Joy Boy's return, which had the Nika DF? Did the Lunarians plant both Treasure Tree Adam and Sun Tree Eve (which is most likely inside the Red Line and reaches Marie Geoise) and escaped to the former after the establishing of the WG? Is there a remnant group of Lunarians currently residing in Elbaph's Astral Realm?

And anyways, why would I be so sure about this? Simple. Morj has mentioned a lot of times that Elbaph's Legoland prologue is a miniature version of the rest of the arc, both literally and thematically, foreshadowing not only the events that have transpired but also possibly the arc's climax (Imu being defeated just like Road cosplaying as a fake Sun God). The Legoland in question is not only a fake mini-Elbaph, with even an "Yggdrassil" posing as a mini-Adam Tree to boot, but how was this place actually called?

It was the Land of Gods (神々の国, Kamigami no Kuni, literally Land of Many Gods).

TL;DR: The Lunarian's home on the top of the Red Line was called Elbaph, and that name was later adopted by the giants.

As you can guess this opens a whole new set of questions and hypothesizing for which I have no answer lol. But I'm willing to bet money on the Lunarians' Kingdom being called Elbaph or, at the very least El-something (and following the same kanji reading I previously laid out).

BONUS TRACK ABOUT WINGED RACES AND GIANTS HAVING A DEEPER LINK IF YOU WANT TO ENTERTAIN THE THOUGHT:

Wanna know about two characters whose names are related? It's these two:

Yes, Hajrudin's name most likely references Odin to complement Loki's namesake and also his status as royalty... but also in Japanese his name is very very similar to Hayreddin "Barbarossa".

Hajrudin: ハイルディン

Hayreddin: ハイレッディン

That reference isn't there for no reason at all. Hayreddin was a pretty infamous corsair who ended up as an admiral in the Ottoman Empire's navy. And the Barbarossa (Redbeard) nickname? He inherited it from his elder brother, Oruç Reis... which is where Urouge's name and real life inspiration comes from.