Mythology and Pantheons: The Elves of Windemere Crossing and the Goddess Ran

As I am reading a book on Norse mythology (I had no idea Odin had several sons!) I think I'll pull some of those gods and goddesses into my own little fantasy world. The pirate Elves that run the Silver Pirate (and there are a number of half-Elves when I re-read that) may often use the curse "Let Ran take them down!".

In Norse mythology:

Ran is a goddess and a personification of the sea in Norse mythology. She is the wife of Aegir, the sea god, and the mother of nine daughters who personify waves. She is frequently associated with a net, which she uses to capture sea-goers and drag them into the depths of the ocean. She is also seen as a protector and a guide for those who travel on the sea, and a symbol of the vastness, mystery, and transformation of the ocean.

For my world, she is a separate pantheon than the one I started 40+ years ago in college. She has 9 daughters who personify the waves. I'll try to explore that later, seeing as there are many waves from the smallest ripple to a tsunami that can take out a city.

But for our Elves of the Silver Pirate, Ran is both a blessing and a curse. They pray to her for safe voyages, as well as blame her for sailors lost at sea. Now at the edge of a desert, the Elves do not pray or offer many observances for the goddess. They are frustrated with the curse that brought them here. The cacklemar (a fat seagull looking bird) is nicknamed Ran's Messenger. Being fat and unable to fly, Nomehi Wiridea, the inn's owner, still offers the bird mackerel she has shipped from the ocean, praying to be allowed back to the sea. The cacklemar is an odd bird found in the Wex's Drift supplement. If my players ever get to an ocean, I'll use that as it seems like a lot of fun. In the meantime, the Silver Pirate NPCs know about the Drift and it may come up in conversation or as rumors. Along with the Amazons - Nomehi has her suspicions about the Burgermiester of Windemere Crossing.

AI generated sea goddess

Now we've nine daughters to deal with if I really want to expand out the pantheon for them, though I may stick with the Norse myths for the Sea Elves gods and goddesses, or at least my interpretation of those myths. Do the Elves deal with Aegir, the god of the sea? Or is he just a sea god of a particular sea?

Which brings to mind: are the gods and goddesses universal in my world, or do they have some sort of geophysical or cultural ties to a more restricted area? If I recall, Tery Pratchett's gods and goddesses depended on their followers' faith for their strength (and actually, that is a is pretty common idea across a lot of history and fiction, I just remember it being specifically mentioned in his books). While I have my central pantheon that I am bit by bit fleshing out, there can be many others out there as well. 

Where this also comes to mind is that my next game (the OSE game I've been slowly prepping for) has a druid, and I've asked the player to come up with that druid's specific religion or god or whatever. Part of my shared world-building process. He is very imaginative so  I am sure he'll have something good that I can hang some game hooks off of.