The Yandere Sonia and Gundham but you just wrote was so good! I was wondering what some of the restrictions Hinata would be facing as a consort are, and whether Gundham would be facing the same restrictions despite him not being the darling in this situation (or is he both Sonia’s darling and Yandere for Hinata).
Your writing is so cool, thanks for sharing it with us!!
Gundham is subject to the legal limitations of a consort, but Sonia chooses to give him more agency than Hajime because they're both yanderes for Hajime. She could choose to exercise her powers over Gundham if she wanted to, but the current status quo is that she and Gundham are enough on the same page that there's no need.
(And a lot of this assumes that the three of them will soon be living in Novoselic together.)
As for what the limitations are, in the interest of going full gilded cage with it, I'm going to say that in Novoselic, consorts need their royal's permission to:
Marry anyone else. My phrasing of this in the previous post left it vague as to whether Sonia meant that they can't marry anyone else at all or just not without their royal's permission. It's the latter. Which theoretically isn't too bad, since theoretically a person becomes a consort as a willing romantic thing and not under duress, meaning this rule would just be legal polyamory; you're the royal's consort and you're allowed to marry someone else if they say it's okay! But in the case where they are forced to agree to being a consort, it basically means Hajime's romantic options are limited to Sonia and Gundham. (When the queen has multiple consorts, romance between those consorts kind of just doesn't count as anything, legally, so him being with Gundham is fine.)
Travel within or from Novoselic, in pretty much any capacity. This will most obviously come into play if they try to get on a plane, train, or bus without permission (in which case they'd be barred from boarding), but also they're technically not allowed to drive without permission. For the most part, this only matters if they get pulled over.
Purchase firearms, which is basically just a throwaway comment based on Novoselic's casually militant vibes.
Undergo certain medical procedures. This one shouldn't come up at all, on account of Sonia's cool.
Buy land. Shouldn't come up because Hajime doesn't want a house or land in Novoselic; if he doesn't want to live in the palace, then he wants to go back to Japan. But Sonia might buy Gundham some land to practice his breeding talent.
I'm going to say a consort is legally allowed to leave the palace on foot or horseback without permission, but that doesn't mean Sonia can't just tell the guards to prevent Hajime from leaving. (The law is one thing, but she can still give orders.) Most likely, she'd make it so Hajime is allowed to walk to Gundham's land and maybe the shops and stores nearest to the palace, but no farther.
Within the constraints of all of these rules, Sonia wouldn't be too controlling. Once she's got him in the palace, he can wander and do whatever he likes. He can be rude, he can break stuff, it's fine. (He probably won't, but if he did, she would take it in stride.)
But also, I'm going to say that all of the staff speaks exclusively Novoselician. Even if they can speak Japanese, they don't. Just to make him a little more reliant on her.