To settle this Vodani nonsense once and for all as it is also something I reject. I am using the latest info from the post Rev had shared earlier in the thread, I typed it out so I could highlight a few things:
Fabled Atlantis represented the pinnacle of human achievement in ancient times. In an era when much of the globe was under the heel of monstrous Deviants, the continent functioned as a living library that preserved much of humanity’s cultural and scientific heritage. Although it was sent crashing to the ocean floor, Atlantis survived the seismic event precipitated by the Great Cataclysm of 18,000 BCE.
Miraculously, it was not only the continent’s robust architecture that endured but also some of its inhabitants. A fraction of Atlanteans survived the upheaval, their bodies adapting so that they could live in an aquatic environment. What ultimately precipitated this change is unknown*. Some believe it to be the result of arcane sorcery, while others speculate that advanced science was responsible for the mutation.
What is certain is that the Atlanteans came into contact with natural water-breathers soon after finding themselves adrift in the Atlantic Ocean.**
The Vodani was a band of aquatic extraterrestrials who had traveled some years earlier to Earth’s seas through a portal from the water world of Vodan. The two people interacted extensively and from this intermingling, a new race was born - Homo Mermanus***. This emergent species was instinctively nomadic, spreading out across the vast seabed, forming countless small tribes and establishing numerous underwater principalities.
Centuries after this first migration, a band of nomadic barbarians returned to the submerged ruins of Atlantis****. They established a permanent settlement on the site and restored many of the damaged buildings. They embraced the philosophy and science-based culture of their forebears. They referred to each other as Atlanteans and saw themselves as inheritors of a historically important legacy.
*The original on earth water breathers were from the lost city of Atlantis. It's very clearly stated their bodies evolved in some way, magical or scientific, to become water breathers.
** After they were in the water (it is not stated for how long they were alone in the seas, only that the Vodani showed up AFTER they had become water breathers.) While in The Best Defense: Namor, the Vodani consider themselves to be the original Earth Water breathers that means nothing imo because they might have thought they were alone for years before encountering the first band of nomadic Atlanteans. Or they are simply arrogant and liars since we already know that the King of Vodan wanted to trick/use Namor for his benefit. Either way their story has holes, and so we shouldn't rush to consider they were telling the whole truth.
*** Again it does not state how many years the Atlanteans were water breathers only that the Vodani spent some years in the oceans, which are very big, and came into contact with the Atlanteans, the bloodlines/water races intermingled and some were born part vodani/atlantean. At this point I consider Vodan and it's people like that of Tamara Rahn, from the water plant Laab, their water breathing race called Banari. The Sub-Mariner (1968) #58 - first appearance.
**** Again this would line up with what Rev says for the nomadic homo mermanus backstories in the comics.
I really don't understand why we should change all of the present Atlantean History that states several times they are descended from the original Atlantis, and evolved to become water breathers because as far as I am concerned the Vodan are just another in a long line of attempted explanations by writers who can't even agree on what the history should be. A small example below:
Other backstories from Atlantis as collected by me so far, still working on this list as I'm trying to find stories of Altantis centered recollections:
1. Fantastic Four (1961) Annual 1 - Recap of who Namor is as told by Reed Richards
2. The Sub-Mariner (1968) #38 - Namor thinks back on his ancestors
3. Man Thing (1997) #7-8 - Namor travels through time to meet with the Goddess Celtio and sees Atlantis in it's heyday.
4. The Sub-Mariner (1968) #62-66 Kamuu the Atlantean Nobleman and his wife, Zartra, a Lemurian born woman - Tales of Atlantis
5. Spectacular Spider-Man (1976) Annual 9 - Neptune & Ossem & the Serpent Crown
6. Incredible Hercules (2008) #123 Atlantean/Amazon war - I generally discount this and don't really think it's canon
Although I know not everyone reads Golden Age, especially the current writers, and most people dismiss the golden age stories I do feel it is important that Namor claims to be descended from Atlantis in Sub-Mariner Comics (1949) #31 now this was BEFORE Aquaman's change into being an Atlantean Prince. While I think his story about the magnets to Betty was a tall fish tale meant to tease her with, I do think/accept Namor's claim of being Atlantean royalty before Aquaman. I know Everett didn't see the Atlanteans as Atlanteans at first calling them Sub-Mariners but it still stands that other contributors laid Namor's claim to Atlantean royalty before DC.
EDIT: ANOTHER VERY IMPORTANT THING TO CONSIDER! If the Vodani and Atlanteans intermingled while there was a sect of Atlanteans who became the Atlanteans we know today and how only certain Atlanteans are of noble blood/connected to Neptune, then it is not beyond our realm of imagination to assume that Namor and his family were of the original descendants of Atlantis aka "pure blooded atlanteans" while others who intermingled with the Vodani are not, hence why Namor's family/other nobles have more claim to the Throne of Atlantis. This is just me speculating of course. In the end I would just treat the Vodani as Tamara Rahn, the Lemurians, Trition of the Inhumans, etc, they are just another "alien" race of water breathers who have connections to Earth.