• Nova: With such a huge age difference between them, Ryan acts more like a third parent to Nova rather than a sibling; though Nova's adamant on maintaining their siblingness, instead- which already causes a bit of a conflict between them. They have a fairly positive & loving family bond, & would do anything for each other, but they're certainly not without their issues. ...And while they might seem like polar opposites, Nova being more bold & Ryan being more calm, they're actually a lot more similar than anyone thinks.
  
    Nova sometimes intentionally tries to annoy Ryan in an effort to goad him into a typical sibling argument, even if Ryan never really takes the bait, but ze's also genuinely frustrated at him for coddling them so much, to the point where they can't take two steps without Ryan asking her if she needs help, or go to bed without Ryan coming to remind her to brush her teeth when xe's literally already in the middle of doing that. Nova does genuinely admire & look up to Ryan, but they're hurt by the fact that he doesn't seem to trust doom with anything. Part of xyr desire to prove spaceself, is to finally make him proud.

  Meanwhile, Ryan constantly worries for Nova's wellbeing, often to a smothering degree. He takes his responsibility as an older brother... probably too seriously. He's worried about hurting Nova's feelings, so he refrains from giving Nova any sort of critique, or enforcing any consequences; instead opting to take over whatever situations Nova's gotten into, himself. He kind of... projects his own experiences with failure onto Nova, assuming that she'll have the same emotional reaction as he does. So he tries to shield Nova, instead- not realising that he can't do this for their whole lives, & Nova's got tougher skin than he thinks.

• Tyler: Ryan & Tyler first met online as teens, having read each others' fanfics about their favourite anime, becoming fast friends. As the two grew older & they realised they would be attending the same college, they befriended each other in real life, too! The rest is history. But while they do enjoy having dumb fun together, their friendship isn't the constant cheerfulness others might expect.

  When they're alone together; they're more melancholic & introspective with each other than they would be with others, sometimes leading to long, existential conversations. They both feel like the other's the only person who really 'gets' it, when it comes to plastering on a smile for the sake of others. They do genuinely have fun with each other, but also drop their smiles & open up about their uglier emotions & vulnerabilities more readily. They have an inside joke with each other about being like a duo of theatre masks, sometimes calling each other 'Comedy' or 'Sadness' as interchangeable nicknames.

  Neither of them fully realise it, but they're kind of... jealous of each other. Tyler's jealous of Ryan for being so effortlessly capable & intelligent, while Ryan's jealous of Tyler's ability to remain optimistic despite making so many mistakes. On better days, it's a source of admiration & appreciation for each other. On worse days, it's a source of resentment & envy. Still, they're both incredibly patient with each other- Ryan doesn't look down on Tyler for not having the same knowledge he does, and Tyler doesn't judge Ryan for not always having his composure together.

• Emiko: While they're not particularly close, Emiko & Ryan are generally on good terms & consider each other friends; having been introduced to each other online through Tyler. While Emiko was initially wary of interacting with an online stranger, finding his gift-giving attempts & sweet personality too-good-to-be-true; once they met in college, she realised Ryan couldn't hurt a fly even if he tried. Likewise, Ryan found Emiko's headstrongness to be intimidating at first, feeling hurt at her coldness, but grew fond over the years as he saw past her walls.

  They're both mutually worried about each other's emotional well-being; especially when it comes to their similar anxieties about opening up to other people & their shared habit of hiding behind walls. ...Neither of them are, uh... really good at expressing this to each other, though. But they both try, even if it can get awkward. It's not exactly easy confronting someone else about problems that you also have & needing to take your own advice in order to set a good example.

  Emiko's trying to get Ryan to loosen up & have more mischievous fun, inviting him to tag along when she's up to a harmless prank & trying to encourage him to get a little more creative with his robotics projects. Meanwhile, Ryan's trying to let Emiko know she's in safe company & doesn't always have to be on guard for danger. They're both trying to make sure each other's comfortable, which they're both deeply grateful to each other for.

• Zeke: Ryan & Zeke pretty much fell in love at first sight; or, rather, love at first nerd-talk. Being tasked to work together for a project in one of their shared college modules, they were the first to match each other in terms of both scientific prowess & passion for the subject, easily understanding & building upon each other's ideas; an unexpected, though certainly not unwelcome change for them both, quickly growing into a mutual crush.

  For Zeke, Ryan's presence was the first taste he's ever had of genuine & no-strings-attached human interaction. At first, he was unsure of what to make of Ryan's straightforward compassion, though quickly growing fond & attached. Ryan, meanwhile, found Zeke's awkwardness to be incredibly cute & endearing. Though Ryan was concerned by Zeke's closed-off-ness & lying habit, he never really connected the dots, assuming Zeke was just... like that, and only needed a friend & fresh air.

  After getting to know each other more, their bond grew beyond just being nerds together, when they both realised they had issues with perfectionism & making mistakes, as well as being concerned for their younger siblings. When it came to their shared perfectionism, between Ryan's insecurities & Zeke's history; it was kind of a "If I'm allowed to mess up sometimes & be worthy of love regardless, then so are you," deal; reassuring & bringing each other out of their shells. Seeing Ryan & Nova's bond was what taught Zeke about what an actually healthy sibling bond should look like; while seeing Zeke & Adam's estrangement was what taught Ryan about what could happen if Ryan continued not listening to Nova.

•   He is hearing-impaired (enough to need a hearing aid) but not fully 100% zero-noise deaf. He can hear more or less just fine when he has the hearing aid on. When he's not wearing the aid (like at home or sleeping or if he's just minding his own business & not expecting to have that many conversations), things sound garbled & unclear.

•   Insomniac. Sir please go to bed at a reasonable time.

•   The sword is his favourite creation; one of the few projects he's let himself just fully indulge & have fun with. ...He keeps it in his pocket & didn't let anyone see it until the events of canon take place & he has to use it for combat; because he's afraid others will think he's being silly & wasting resources on something so stupid.

•   Has a few more nicknames other than Ryan (mostly from Nova), including but not limited to: Ry, Rhino, Origami, 'O', Dr. Watson, & Baby Blue.

•   Doesn't know a lot of sign language, apart from basic words & phrases, because he became hard-of-hearing later in life & was already busy learning Japanese; so, he mainly he types or writes instead. Gradually gets better at signing as the story progresses for the sake of convenience.

•   Tugs at his sleeves as a nervous habit; subconsciously rolling them down when he's especially on-guard.

•   Has a very calm & polite, somewhat formal manner of speaking, saying things like "Perhaps," "Well, you see-" "But of course," but it still has the emotional variance & tone you'd expect from a more casual speaker; instead of just being stoic & impersonal like Zeke. It's like he's trying to get a perfect grade in an oral exam. "Oh, but of course! How interesting; I don't quite know if it'll work... maybe if I do this-? Nova- please don't touch that, you'll get burned!"

If he's particularly distressed or tired & just does not have the energy to get his words out the way he prefers, he just uses writing/typing instead. His writing style is quicker with more abbreviations, to get the message across faster, e.g; "Cld u gimme abt 20 mins" ("Could you give me about 20 minutes?").

•   His arc is basically him becoming more & more loose & creative instead of worrying about the expectations of others. Unhinged pixie dream boy my beloved <3. He gets really into painting later on, and starts decorating his gadgets in a way he didn't feel safe doing before because it'd be deemed "too informal". As his confidence and artistry grows, so does the amount of paint on his hands and clothes.