The picture is adorable! Kali and Ogin in her hair, and is that Kerisa 2.0 in her arms? D'awww!
....
Although for some reason the armor is really bugging me. It's NICE armor don't get me wrong, but it just doesn't fit the image I get of her Moonsilver plate from your descriptions of it. I envision something like
Witchblade armor and this is a lot... hm. Bulkier?
Remember - it's still superheavy plate. Sure, it's lithe and organic, but it's lithe and organic in the style of some of the more armoured female Warframes, not in the style of "silver body paint". It protects her by having nice and solid layers of magical silver between her and attackers. And I suspect the "feathers" function as crumple zones too, absorbing the strength of a blow and then springing back into shape.
Yeah. Szoreny. I maybe didn't get any nightmares of my own from that nightmare-sequence, but it was still like someone had slowly started dripping cold water down my spine while I was reading it. The worst part was realizing that this wasn't anything external inserted into Keris' thought-process, but her own envy and insecurities magnified just a little bit more and given free reign. The cute bit with Oula and Rathan immediately afterwards was much needed and appreciated, until you are hit by the cold sudden realization of that the nightmare triggered the evolution of Oula, and what this implies. Though were are still at zero bodies of suspected love-rivals (that we know of) in the latest available session, so maybe things will turn out okay? Please?
So, there's a funny story here about the evolution of the evolutions of Rathan's demons.
In the original plans, his grown up keruby were going to be a comment on toxic masculinity and patriarchy. You had the moon wives, who had to
obey the one who had their heart and got limit if they disobeyed them, and you had the other ones, who got stronger the more things loved them and so when they were young were dashing crusaders for justice, but as they got older and got more power realised how much they benefited from how things were right now and took the easy path of building up stockpiles of moon wife hearts and therefore getting harems of moon wives (who back then could be either lioness-headed women or women-headed lionesses). And the Sea was going to turn into this mess of gender-politics-based metaphors.
But then
@Aleph decided to associate Rathan with Szoreny instead of SWLIHN, Rathan grew up more in his time outside, and more than that Oula developed into a character. And Oula as a character is not particularly obedient (even if she's loyal), as well as being decidedly wilful and Keris's adorable little protege.
And the thing is, Keris has never really seen "love" and "obedience" as very related.
As a result, moon wives underwent a significant rework. Some of it was cosmetic - reshaping things with mercury as sculptors, rather than singing up stone by making crystal grow, and becoming dolphin-themed rather than lioness-themed. But the heart of the change was altering their limit thing slightly which totally changed what they are. They don't have to obey their loved one; they have to act in their love's best interests
as they see them.
And that's a much less constraining thing, that makes moon wives far more dangerous and far more able to push their own wants. Now building a moon wife harem isn't just a question of getting hold of their heart. Now the would-be harem builder has to consider the real and pressing risk that the first moon wife will go "She's corrupting him! I'm going to gut her!" and that's
far more fitting for a Kerisian demon and also for a grown up wave cherub. And sure, you might be able to find two moon wives who get along and can fit an arrangement where they don't mind sharing you, but what about the third? And the fourth?
With these changes to the moon wives, as
@Aleph said, trying to build a harem of them is like trying to build a love polygon where every node past the first is a yandere.
The end result is that Szoreny in general, and Oula in particular, have made the future of the Sea much more egalitarian in how the two grown-up breeds interact. Put simply, Oula is not going to let the same kind of culture develop, because she is of the opinion that it's not in his best interests (and she will pull in Keris if needed). Oula is not going to give up her duchy nor her position as his general nor will she tolerate other wives. There might be room for compromise on temporary concubines, but as far as she's concerned, she's the first girl, she's the student of her mother-in-law-to-be, and she's won. Now, yes, Oula might be an exceptional, heroic demon, but she's very willing to set a precedent (and will likely gleefully do so when she realises the other breed can grow more powerful by being more loved, because she wants to be the most powerful 1CD in the Sea).
One of Oula's traits I actually really like is that she's only soft and deredere around Rathan - and even then she's willing to roll her eyes and humour him while guiding him away from what she thinks is a mistake. The rest of the time she's driven, smart, ambitious, and kind of bitchy. The first time she spends time around Rounen post-maturing, she takes the chance to remind him he's only the second one to mature, and she's willing to talk back to Rathan's siblings despite the fact they're 2CD-level and she's a 1CD. She's a dangerous lady and would be even if she wasn't also a demonic yandere.
(One of the other consequences of this is the precedent set that the first of a grown-up kerub breed has the power to set the template that others can follow. Rounen has shaped the future path for the dragon aides too because of this. It also means that later examples of the breed will find the growing-up process to be a bit more radical in how it changes them, because they don't have the "you were already like that" of the firstborn.)