Guess
After thinking for a long while, Rain didn't come up with any solution to the problem of the sea folk and the ocean covered in dust. Seara had to help him with that, and together, they brainstormed some ideas.
Naturally, a bunch of the sea folk had to help with that to make things feasible. With that in mind, they considered a bunch of things. Creating wind walls above the underwater capital to make them receive sunlight after two weeks without it, but it would be one heck of wind walls since they had to reach beyond the dust clouds. Rain couldn't create relics of that level since the limits of the relics were his own skills.