Oh, my god, YES. I imagine Sukuna having taken Yuuji in after his parents died (under somewhat mysterious circumstances perhaps) and the people being so touched by their emperor's generosity toward his brother's son 🥹

Since Sukuna has no son of his own, Yuuji is expected to be named his heir, an expectation that seems even more likely when statues of Yuuji start to appear. They pop up all around Rome, often where statues of Sukuna himself stand. Nothing seems off about that, until word starts to spread that there also are several in Sukuna's home, and that they are of a rather different nature.

In almost every room in the residence, there are life-size statues of Yuuji in various states of undress. Some of them are eerily close to the statues men commission of their wives, with Yuuji showing loyalty and affection, and even symbols of fertility.

Those who witness them can barely look, turning their faces away or even to the ground in their presence, something that the Emperor seems to find highly amusing. He often steers people's attention to the statues, asking them their opinion on the likeness, pointing out concerning details, and wondering if they think he should commission the same artist again or if they can recommend someone else.

If Yuuji is present, he blushes crimson, further strenghtening the suspicion that Sukuna doesn’t see him as his heir. It becomes a well-known secret that their relationship is anything but proper, but what can they do? Sukuna is the Emperor, and despite his degeneracy, the army supports him completely. Anyone who dares to try and speak to him about Yuuji ends up demoted, by losing their seat at the senate or worse.

Sukuna spends his life with Yuuji by his side. Never marrying. Never having children. Never appointing an heir.

Frankly, he doesn’t care what happens once he dies. As long as he can have Yuuji, he will rule Rome with the iron fist that makes it possible to keep him.

Jin is 50% shark/50% mer, and Kaori/kenjaku a regular mer. She was most likely drawn to Jin because of his unusual heritage.

Regarding Yuuji’s family situation, I've been thinking that Kaori/Ken has had some unusual children before. Like, Choso is off somewhere, being an orca/mer mix or something, haha. Yuuji probably doesn't know he exists 🥲

I haven't decided if Kaori is around or not. She might've taken off to find more interesting partners, or she's just not as worried about Yuuji and therefor not as involved as Jin is. She'd probably love that her baby was mated to a real shark, though😆

Sukuna might've eaten the mate. Whoever they were pissed him off too many times for him to put up with them anymore. Needless to say, he didn't care about them even to begin with. He just figured it was time for a mate and later regretted his choice. And now he dove head-first into a new relationship so he learned literally nothing LMFAO

I imagine the shoal being nomads, so they don't have houses, but otherwise they're pretty advanced. They have doctors, inventors, scholars, etc, so they've figured out how to make glasses at some point. They just stick to inventing small things since they move around a lot.

The only similarity Yuuji sees between Sukuna, Jin, and himself are the colors that he notices when they first meet. He just thinks it's a common shark color, but it really isn't. The thought that they could be related definitely doesn’t strike him. Sukuna thinks Jin has been dead for well over twenty years so he doesn't think Yuuji can have any relation either (not that I think he'd care since he's the type to take what he wants regardless of the consequences).

I hope that answered some of the questions 🩷 Thank you for asking 😊🩷🩷🩷