I honest to god tried to put in replirs but the world limit was annoying me so. Okay, hear me out.
He's not even an early family member. He comes after the central fam is, at this point, used to Bruce's chronic adoption syndrome. So here comes a Buff ass, full-grown Rok Soo just... Showing up one day on the couch. Snoozing, reading, eating cookies. Duke thinks it's a family friend he hasn't been introduced, until he hears the man talking to Alfred about 'how everyone else got adopted'. Has to check with Dick that he's the oldest one, 'like are you SURE sure you're the eldest still.' 'What do you mean still?¿' and the little shit hangs up with a little text 'oh nothing dw abt it :)' and goes to yk, say hi.
(You'd think, Oh well, as soon as Bruce gets the adoption papers, everyone talks to everyone else about it; but let me tell you thats not how it happens on big families, hell, the Bats are more dysfunctional than Most even. So everyone gets to know Rok Soo in the most eclectic way ever.)
Meanwhile Rok Soo is just going with Alfred 'huh, so this kid (Tim) strongarmed his way into the family? What for? Oh, to take care of someone else? Couldn't be me' the hypocrite times a thousand says. No one can call him out on it yet.
I think the funniest encounter would be Jasons. Rok Soo does his business as usual, and ends up systematically dismantling some part of the underground Red Hood's been in a territory dispute abt or smth, and on his side, Jason isn't surprised abt More goddamn children. But he doesn't GO to the fam enough to see shit for himself and doesn't want to end up having a conniption about it in the middle of Important Shit.
So all he knows is, okay, new kid. Give it a day. A week. A month at latest, and another bat will be flying around and he'll have to sit down and explain that, no, this is my side of the show, No One crosses this street unless necessary. He knows his name and thats enough for now.
He gets smacked with it in the face when this brick house of a man is on a gang meeting (and very pointesly doesnt want to be here???), refuses to lift a finger, but with the usual fanfare explosions go everywhere. Someone called Rok Soo the same ostentatious gang name he's been hearing. Then it clicks. The goons getting poached under him. Another fucker rising from the woodwork trying to make the poor side of town somehow not as much of a shithole but in ways it complicates the shit out of his own operations. The new fucking bat.