Okay, by now I am beginning to buy the argument that the dice won't let us have the Death Domain. Because darn it, it's like clockwork.
Also, I would like to throw my own hat into the ring appearence wise. I was thinking of taking something a bit Hindu inspired, as their depictions of deities work really well to make something "Human but obviously not", and applying it to what has no doubt become a symbol of ours. Bonus points for keeping it "gender unknown", as I am 88% sure no one else knows how to properly sex carps.
[X] Yes. Claim a form for yourself and show it to the people.
-[X] A large, fourlegged carp with a human arm coming out of every scale
Obviously the extra arms are for showing that Proud Waters can heal and help any amount of living beings in the metaphorical sense, and for giving our people lots of headpats in the literal.
Also, on the assumption that approval voting is allowed:
[X] Yes. Claim a form for yourself and show it to the people.
-[X] One of the People, of indeterminable gender, with hair like kelp and eyes like pearls, with skin of an ocean blue hue, possessing a stern, proud, but kindly presentation.
I like this one, it has a nice, ethereal design. If we're gonna be a humanoid, this is what I want Proud Waters to look like. Except maybe with more limbs.
[X] Yes. Claim a form for yourself and show it to the people.
-[X] A whirlpool, dragging evil like the Devourer to the seafloor where they are transformed into vibrant sea life.
I really like the idea of just having Proud Waters be some kind of "natural" phenomenon that people are worshipping. I am not sure a whirlpool is the best fit for that, considering that to humans at this point whirlpools are large, destructive forces that protect no one and cannot be bargained with, but I have no idea what other shape would be better and I will admit the image of our people worshipping a giant healing whirlpool is amazing.