Oooooh, now this could be fun!! Like, Roche shows up in Vergen after/during the battle (and kills King Henselt, but they're down with that), and they know that Roche and the Blue Stripes were with Kaedwen's forces, at least before the battle. So they must assume that there is some treachery planned here. And on his side... okay, he wants to catch the kingslayer, yes. But also, he just lost his entire world. And revenge is all well and good, but it doesn't bring them back.
So I can see him getting arrested automatically by dwarves or squirrels who recognize him. But it's Iorveth who notices that something's not right. Roche is still angry at everything, but now it's directed inward, rather than used to lash out at prison guards and such. And looking at Roche, it is so clear to Iorveth that something is broken. But of course Roche can't just say what happened, so it becomes an interrogation. But Roche is a stubborn fucker, so Iorveth all "welp, okay, torture time. I have no mixed feelings about this."
Except then the moment comes to do it - and Saskia is aware of what's happening, but even though she disapproves of torture, she can acknowledge that Iorveth knows Roche better and she'll trust his judgement. (But like, for real, torture doesn't work. We have literal studies proving torture doesn't work). So anyway, Saskia allows Iorveth to do what he thinks best and Iorveth is all "okay, I can do this!"
Except when he actually starts, Roche is just... blank. The torture he's putting himself through internally is nothing compared to any beating Iorveth could manage. And Iorveth is totally not worried, but like... that's not right. He wants his Roche back, the Roche that screams and yells and chases him relentlessly. Not this quiet, dead inside Roche who looks at him with tired, defeated eyes and doesn't even care anymore.
So Iorveth has a moment of crisis and goes to Saskia (who manages to refrain from telling him 'I told you so' re: torture). And she suggests that if Roche is consumed by his own pain, then what he needs is some gentleness and kindness. And Iorveth is all ???? can I even do that anymore??? but he doesn't have any better ideas. So he has Roche brought to him from his cell, and instead of beating him or hurting him, Iorveth gently cleans him? Like, soft touches and gentle washing with a sponge bath, and then maybe even a hot tub to soak in after and some fresh clothes? And Roche is... only sorta there at first. But the gentleness works, and he probably comes back to himself sometime between Iorveth washing him and Iorveth putting him in a tub to soak and he's just ???? wtf???? But it's... really nice, actually, and it's fucking weird, but Roche hasn't had any control over his life since the moment Dethmold ordered his men murdered, so why not just go along with the weirdness?
And I think eventually this leads to them like... releasing Roche 'on probation', which basically just means that Iorveth is still watching over him, but he is free to wander around Vergen and such. And over time, Iorveth actually sees signs of his Roche again. And he's sadder and more burdened now, but he's no longer blank and dead and that's something.
Iorveth knows his Roche is really back when he comes 'home' to wherever they're living (with Saskia? idk) and is ranting and raving about how annoying some of the peasants and shit in Saskia's council are and why they're making this shit difficult. And Roche listens and then actually suggests a solution. And it's... it's not a nice solution, but it is an effective one. And Iorveth grins and maybe does something stupid like kiss his Roche as a welcome back, but it's just a peck and then he runs out the door to go take care of the thing and doesn't even realize exactly what he did until later, when he turns bright fucking red in the middle of enacting the solution.
Fortunately, Roche is suprised, but not offended. He's a little bit still in the 'I have no control over my life, so I will just go with the flow' mindset, but I think maybe for the first time in a while, he starts thinking about how he could do things to change that. Like, he could just decide to kiss Iorveth back, and that would be taking control of his life and circumstances a little. But also, that's fucking scary, so maybe it takes him a while to actually do. So like, they don't really talk about the kiss, and Iorveth is just relieved it didn't ruin shit.
But eventually, maybe while they soak together in a hot bath? Roche decides he's ready. Maybe it's something Iorveth says or does or maybe it's just the way Iorveth looks in that moment, and Roche thinks about all that Iorveth has done for him and all the kindness he's been shown even when it wasn't necessarily warranted. And he thinks about how hard that first offering of kindess must have been. But Iorveth did it, and kept doing it, and now Roche feels less like a cloud is hanging over him and... well. It's only right he be courageous and do something hard in return, right?
So he kisses Iorveth and, miraculously, Iorveth kisses him back! And it might take them a while to actually talk about this, 'cause they're both idiots, but in the meantime, they just kind of enjoy that their life can now include kisses, and that's kinda nice.
Wow, this has gotten long, hasn't it? But I feel like it could go two ways:
1. Saskia beats some sense into them and tells them to fucking talk to each other.
2. One of them gets sexually/romantically frustrated enough to confront and/or jump the other?
Damn okay, I wanna write this now. Maybe it's a bit of both? Like, Iorveth is pining at Saskia and she's just like, "hey, dumbass, try using your words," so he goes back home/goes to Roche. But Roche is also really frustrated, so he maybe jumps Iorveth before Iorveth can say much? Which leads to them half-talking, half-fucking, but afterwards, they definitely talk properly.