Getting sandrock verse thoughts out of my system don't mind me
I think this verse's Seb is the one who's the most rough around the edges. He left home at 18 and traveled alone for 8 years after, living off of monster hunting gigs as he wandered from place to place within the Free Cities. This meant his income was very unsteady, and sometimes he had to live off the land via hunting or just go hungry some days if he couldn't find anything. If he got hurt and was too far out in the wilderness to seek medical attention, he had to be his own attention. Take what he could from what he could find in the local flora and just hoping he didn't die of an infection in the process.
His social engagement with others was kept pretty strictly professional. Tell him what needs doing, then pay him when it's done. It's easier not to risk getting attached to anyone when he made a point of not settling down anywhere. At most, when money was particularly lacking, he'd end up in someone's bed for just enough gols to get him to wherever his next destination ended up being. It's not an aspect of his life that he talks about much, but he's not necessarily ashamed of it either.
It was a paid service, like everything else, and it gave him the same sort of adrenaline high/dopamine hit to chase as fighting monsters or diving in ruins did too (which kept the Bad Thoughts and Memories at bay). One does what one must to survive.
The help wanted ad for a Builder in Sandrock just happened to come at a time where Seb was flat-broke and HAD to stop somewhere long enough to reasonably rebuild his funds whether he liked it or not. The Eufala Desert wasn't his first--second--third--even fourth choice, but it would keep him busy. Plenty of monsters to be had where fewer people traveled, and surely a run-down town barely on its last leg would need stuff consistently repaired and rebuilt. At the very least, he might be able to scrounge up enough gols off the obvious desperation to be good to bounce once it all inevitably fell apart.
Besides, an Old World buried metropolis sounded ripe for dodging the sun through daytime diving, anyway. Somehow, he saw more net positives than negatives. So, for the first time, he signed an employment contract and hopped on the train.
ALL THAT TO SAY, he dealt with his familial trauma by burying it under years of busywork and fighting/diving and just not thinking about it and it shows sdFGHJ. He's quite blunt and sarcastic and has zero problem calling someone out when he smells bullshit. Can be easily annoyed, depending on the person (tho this gets better over time). Very stubborn, highly independent, can be prone to brutal/vicious anger (also depending on circumstances). Most definitely gives the impression of someone who's had to be the only person in his corner for most of his life and became quite verbally/emotionally/physically scrappy to compensate for it (my man will take any reason to literally fight someone). Can be rough/course/crass with his language, too -- he swears like the son of a sailor around everyone except kids, lmao. And he's never, ever, been one for religion/The Church of the Light.
And yet, surprisingly, once he's adjusted to life in the desert and gotten over himself enough to quit complaining, he shows a remarkable amount of extroversion and empathy. (Part of it is that the game's Builder is just written as generally friendly and enthusiastic by default, but still). Once he starts breaking his own rules regarding distance with other people as the town's inherent charm and heart breaks down his barriers enough to let them in, he's shown to be a snarky, mischievous, fun, supportive and caring person (with a sense of humor as dry as the desert itself).
He's able to slow down and gentle himself with the deeper introverts like Amirah and Fang, match energy with people like Logan and Rocky, and engage with genuine civil intellectual/philosophical debate with folks like Miguel or even Burgess despite being such opposites in nature. And he will NOT hesitate to stand up for someone if they need it (Yan's comments about Mi-an do not go unanswered if he's around to hear them, employer be damned. say that again, asshat, he dares you). Plus, tho the game likes the joke that the Builder can't usually follow Qi's "science talk" (when it's actually pretty direct and not difficult to understand), Seb sincerely enjoys 'geeking out' with him and finds his hypotheses fascinating. (And, rly, who doesn't like space as a concept and wouldn't spend hours with a telescope at night?)
Over time, Sandrock becomes the home he never really had before. What he'd initially dismissed as some big rickety shack on life support occupied by backwoods hicks becomes the place and people he would give his life for without hesitation. He becomes his best self as he falls in love with the sheer tenacity and compassion of those around him, who accepted him even at his worst and showed him what it's like to be cared for more than just what his accomplishments are or what he can do for them.
He signed that contract for a job and actually got bait-and-switch therapy'd instead. Good for him.