(Karal likes Leareth seeing all of his thoughts. Being known like this, not having to put in the effort to word things usefully, not risking giving the wrong impression by saying something or not saying it, the instant feedback when he's missing something and second perspective even when he isn't - it's wonderful, being able to just have all that. There are some things about their shared situation he's not entirely happy about, but this, the thought-reading and the company in his mind, he just straightforwardly likes, and he tries to show the feeling to Leareth as clearly as he can. He would choose this freely, in some hypothetical mad circumstances where that choice would make sense separate from all the rest. If there's anything he feels bad about, it's that the situation requires Leareth to pay more attention to him than Leareth would probably prefer, although he knows there's little point in worrying about it when it's inseparable from everything else.)
...
Karal did very much need to hear all this, for all that it hurts all over again, in a different sharper way. He doesn't mind that it hurts, but he minds that it happened--
Matteir, no, why couldn't he have lived the rest of that one good and full life without some awful death or another, why did he risk it, when he was so afraid...
Not just some awful death - it was Karal's own god who did it. Presumably He had a reason, but... no, it still cannot be right, to hurt someone who's trying to talk, to punish an impulse toward cooperation. It goes against Karal's deepest instinctive principles - in a world full of wrongness, when someone reaches for something even slightly better you have to reach back, or at least not make them regret having tried (the way it would be the worst possible thing to make Leareth regret being kind to him), or else you're abandoning the hope of something better ever happening. It's the same, in a sense, as his newer realization, and as Nayoki's grudge against the gods - for the world to get better you need to let people try well-intentioned new things, even if they won't work, even if they're just blindly groping in some direction they only think might help, you can't punish the attempt or you won't get better ones. If Vkandis Sunlord would do that deliberately, then He is not a god Karal can worship. (He lets himself have the full thought this time, stares at it in his mind and doesn't flinch away from what he just realized. It's true.) And if He did it because He couldn't see what it meant, then that also is a horrible wrongness in the world, that gods are by nature not the sorts of entities that can deserve how people feel about them - and Leareth is right, if not about his methods then at least about his goal. (Or if it was just some awful mistake that doesn't mean either of these things - but it wasn't, Leareth is more careful and more thorough than that, Nayoki said he tried it more than once and of course he did. If it didn't work it's because it can't.)
Then some other awful thing happened, a whole life lost to who knows what. And more lives spent in endless careful attempts to find a better way, because Leareth is like that, Karal has seen enough of him to know he will keep trying no matter what happens - the unyielding certainty of his goal, the endless fundamental strength that will keep him coming back to it, and the almost inhumanly principled mind that won't let him ignore any alternative or complication, not even an unfairness he has already decided not to do anything about. Almost nobody in the world is like this, because almost nobody can stand it - for one lifetime, let alone so many of them, so hard, and so alone.
Nayoki explains the rest, and-- it's the worst part, that it's all such an awful tangled tragedy, that the reason why Leareth's plan has to be this horror instead of some other easier possibility is because Nobody will reach back to him, because if he tries to do something better They will twist it and make it fail. They've admitted no possibility of trust or cooperation, and that's why the awful thing They're trying to avoid has to be that way-- (or maybe They would want to avoid it just as much if it was done without all the death and suffering, but if that's it then Karal doesn't care what They want. --Only for a frustrated moment. He does care - there might still be a good reason, even for that. But if he cannot know it, and will be punished for trying to find out, then it can't really make a difference.) The whole problem is twisted back on itself - the reason why the world can't be better is because people will be hurt for trying--
The thing Karal wants most in the world is for things not to be like this. He cannot have it - or at least he cannot have it until Leareth succeeds. But he can have one little piece of a world in which people can try to trust each other, can reach out to each other and have it help even if everything is tangled and wrong, in which Leareth's honesty and striving gives him more options rather than more constraints. A world in which Leareth doesn't have to worry about Karal's decisions, about his possible opposition or judgment or even just withdrawal - a world in which Leareth can be, on some basic level he feels but can't properly describe, less alone in this. Karal wants so badly - he's wanted for a long time already, without quite letting himself think about it, until everything came together clearly enough to wash away all objections - to give him something better.
I would be yours, if you'll have me.
And immediately he looks at Leareth's quieter thoughts, after having been lost in his own, and adds in a softer mental voice: I'm sorry - you're so tired, and I keep... feeling things. I can wait until you've found your balance.