We fully intended for players to discover the themes and mysteries of Wildmender on their own, so I'm sorry to say, I don't have a solid answer for you.

However, I would like to invite players to discuss their thoughts about the ending here! All of the information we intend to give is there in the game.

Thanks so much for the question,
Jennifer

Now I'm trying to understand if I may have missed something? *sigh*

Sorry if this is a bit of a necro, but the way I interpreted Naia's ending is that Naia sacrificed herself to restore the land by creating the lifeflames with her essence, and that that was her plan all along.

Earlier on in the game the other gods mention Naia "making her choice" and "starting that which can't be stopped". I think that's in reference both to her sacrificing herself and to destroying the tree of life so we can defeat Sellan. When you start crafting lifeflames for Stryge, she says that Naia is "foolish", so I think Stryge also knew what would happen if Naia used too much of her power.

But I don't think Naia is completely gone. She says that she hopes some part of her can see the future you'll create, and the way the camera looks up to the sky afterward implies that she's still out there in some capacity. The Spirit Darters circling around her statue probably aren't just mourning, but also trying to bring her back, sort of like they can with dead plants. I also think that since Naia created the lifeflames using pieces of herself, a little bit of her is still there in all the springs that we restore.

thank you!