Lee Tae-gun. Korea's first and, currently, only S-rank. There are A-rankers who could get the promotion to S-rank, if they wanted to, if they revealed enough of their powers—or, at least, there is one, in Kang Jaeha himself—but this flash in the pan boy was the first one to decide to just go for it and now he's probably learning about how much it sucks to be the center of attention. 

Not that you'd know from just looking at him. He's always gorgeous, stepping out of dungeons, and that's genuinely impressive in itself, but it's even more impressive if Quasar is right that they might be compatible. This implies things about the shape of Lee Tae-gun's backlash, things that suggest he's quite good at self-control, and that he must be holding quite a lot in, to be able to look like that.  So that piques Jaeha's curiosity, and he looks into the boy.

Lee Tae-gun is 21; manifested really late, about a year and a half ago; has had three partners so far, two A-ranks and one B-rank, each lasting a handful of months and ending in the normal way these things do, with them finding partners they're more compatible with. As far as Jaeha can tell, there's nothing particularly out of the ordinary in the boy's history. He's really just very straightforwardly boring. 

And, well, Jaeha is also between partners right now. The story with him is also usually the same: he's never found anyone he had great compatibility with, and they'd all eventually leave, even if they never found someone else. Better alone than with Kang Jaeha. But he doesn't take it personally. He knows they probably want more out of a partnership than he can give. This boy will be no different, they'll spend a while together and help each other survive and eventually the boy will move on and Jaeha won't take it personally either.

So Kang Jaeha is in a meeting room, reading some files and waiting for Lee Tae-gun to arrive so they can figure out whether they'll do business together or not.