Here; a character I've been trying to figure out since what feels like forever now! I knew what kind of character I wanted Luna's child to be, and had a general idea of what type of color-scheme I wanted them to have, but wasn't sure who the other parent should be? I needed to be someone I could see Luna with, and who'd fit as a parent regarding the type of character I wanted their kid to be. I was pretty stuck until I came across DuneFilly 's Luna x Rockhoof nextgen, and realised that he'd be pretty much perfect (also lowkey slapping my forehead for not thinking of him sooner). Just aside from him and Luna having the shared experience of coming from the past to a completely new future, I think their personalities would fit really nicely together
Anyway, this also means I can finally nail down this characters personality and appearence
To sum her up, she is… loud, brave to the point of stupidity, and acts extremely self-assured and over confident.
When she was born, she was extremely tiny (something which has remained a constant through her life -turns out magically enhanced size and strength isn't inheritable, so she got her dad's originally tiny frame), with a mess of golden hair. Rockhoof decided to name her Idunn, after the goddess of youth and guardian of the golden apples. Normally, naming someone directly after the gods tended be viewed as a bit… pretentious, but considering that her mother is essentially a demi-god, Rockhoof felt he could be a bit pretentious in her naming.
Luna was really concerned with making sure Idunn didn't experience the feeling of insecurity and being an outsider as she did, so she and Rockhoof really went all in to make sure she felt secure and confident… it worked a bit too well. She also inherited her parents booming voices, so the result is a pony who doesn't always understand social norms, is extremely loud, and acts very overconfident in everything. She tries to take poeple's feelings into account before acting, but usually doesn't really get them -you have to spell them out to her. If you don't mind her volume or overbearing nature, she can be one of the most loyal and brave ponies you'll ever meet, but a lot of ponies find it a bit difficult.
The one thing she does feel a bit insecure about is appearing as strong and powerful as her father and mother. Take for example her cutie mark: What is it? Why, it's defeating equestia's enemies in glorious combat! (The mark is a tree) Ok then, so… she helps equestria flourish by keeping it's inhabitants safe from any threat! (Aren't flourishing marks usually flowers though?) …She builds equestria's armies to be as strong and everlasting as the mighty world-tree? (…) …ok, yeah, it's gardening, specifically arboriculture. That doesn't sound as intimidating though.
Not that she'd ever disparage gardening or not wish to do it; it is her talent after all, and she does work in the palace gardens every afternoon. She just can't help but wish her talent had been more… striking. Whatever, at least her gardening skills are superb! And her magnificent connection with flora is rivalled only by the masters of the craft, who have spent lifetimes honing their skills! (By which she means the palace gardeners who taught her)