I'd really love a design basked on a Nøkken! I've seen some art pieces of Nøkken that i really adore and i'd love an OC based around one.
From what I know, they're a mythological being that mainly dwells in water and usually has a tall and thin build. I don't know if this is true or not but I also heard they often have violins? Here's some quick reference photos
Nokken , Nokken 2 , and here's a really good reference for the general design of a nokken -> Nokken 3
Here's a Moodboard and a few color palettes to choose from: palette 1 , palette 2 , palette 3 , palette 4
I'd really love to see how you'd draw a Nøkken in your style