In my ongoing mission to assume nothing, that’s a “not equals” sign in panel one, and normal Nanase is on the right (though, admittedly, with hair and a outfit we’ve not seen in canon).
Panel one - Rhoda height and figure Nanase.
Panel two - Diane height and figure Nanase.
Panel three - Um... Shorter but larger curvy Nanase?
Panel four - BEEFY NANASE.
I originally planned to just keep the clothing style the same between panels. I’d sketched it as such at first, but I didn’t really like it for any panel other than the first. I decided to have fun with it, and now I like the results in each panel.
I also like Nanase’s look in the last panel way more than I thought I would. I figured a beefy form Nanase would like would be in order, but I don’t generally draw muscular forms for women that I’m ultimately happy with. This one I like enough that I’ve already thought of several ways it could become a canon form for her.
Granted, in a comic where people can just get spells that reflect them, that's easy enough, but I'd want there to be a character reason she gets the form beyond "that looked neat in non-canon, let's canon that up a bit".