Most of the time, when I do these headcanons, I show the feathers or frills of the head and neck fully extended. It showcases the full extent of it and any markings it may have. But I did a few doodles here with NMM’s fins in a more relaxed position. I also wanted to show off the luminescent markings, and the fact that they aren’t always lit up. She really only flashes them as a sort of threat display, or when doing magic. Most of the time they’re barely visible.
The last thing on the page is my rough sketch for an illustration I’m working on. I’m having some trouble with it at the moment though.
Official headcanon here: