It's A Mystery, Anthropology

When i first saw this I thought, "HAH- too bad that's not a feasible thing, then I could go so many public places while still safely cushioned and laying down!"

She’s Miorine’s former friend from their childhood; they knew each other since ‘before Miorine could remember’ and presumably lost contact after Notrette died and Delling put Miorine on lockdown. They are not exes; they are not (formally) formerly pledged to be bride and groom; that was from their childhood days of playing “house” with each other.

She is the CTO of Langlands, a company in the Benerit Group which specializes in anti-beam paint tech but has branched out into other fields such as food, medicine, and recently, a mobile suit collaborative project with Jeturk. Her twin is the CEO.

Yushura is disabled in the sense of being unable to handle standard (1G) gravity for long, and has a weak grip. The only other clue given is that she checks her “blood Q value” (oxygenation). [!! personal extrapolation] From this it can be inferred that she has low muscle mass, and likely a heart condition, but the cause and diagnosis are unclear.

As for why you’re seeing her in fanfic, and this is my personal conjecture, she makes a convenient plot element that Miorine has strong emotional ties to that is both not a man and not a threat to the primacy of Suletta/Sulemio