Wait Leareth's immortality spell does WHAT.

(Did what, Seldan supposes. It doesn't do anything anymore.) 

See that's an example of a bit of context Leareth could have been leaving out which might conceivably matter for an assessment of his characteristics! Though, uh, him not having it also killed a bunch of people. Causally, not in terms of moral responsibility, not that Blai is the expert on moral responsibility.

:I don't know if he will in fact pay for any such thing. He might or might not consider that something he owes reparations for: Blai stalls.

That sure is a bit of context! Seldan doesn't actually feel like it's at all surprising or in tension with everything they think they know about Leareth's characteristics, and is mostly staring in fascinated horror at the fact that you can even do that. It's hard to think of a coherent moral system under which it would be worse than murdering ten million people, but in some sense it's...creepier. 

...Anyway, the thing Brightstar tried was in fact a stupid plan! That he did not spend even five seconds thinking about the consequences of! Admittedly 'chasing after someone's soul when they die' makes sense as something one would need to do instantly, and there is an important skill in being someone who's capable of forming and acting on a plan in a split second, and if Brightstar survives his twenties then someday he might be very, very good at that. 

Fundamentally, it seems like Brightstar is a hotheaded young fool. There's no shame in that! It's a rather common way for young men to be; every so often you get someone like Treven, who seems like he's had the deliberation of a forty-year-old man since he was a small child, but that's unusual even among Herald-trainees. Seldan himself is pretty sure he was once a hotheaded young fool, and the only reason he made fewer wild and insane decisions was moral luck and having a Companion. 

Apart from having a Companion, which seems unlikely to be in the cards for Brightstar, Seldan feels like the standard wisdom for surviving - and not getting other people killed - until you learn some wisdom and maturity is...having trusted friends and mentors with better judgement, and listening to them if they yell at you that you're doing something idiotic? Brightstar could definitely stand to do more of that. He's lucky to have friends who are very forgiving people, and Jisa might be herself a bit of a hotheaded young fool but she at least does have a Companion. It sounds like perhaps Brightstar was previously trying to use the Star-Eyed Goddess as his older and wiser mentor, which is - kind of understandable, that's got to be a rather common way of relating to one's god - but it does not, in fact, seem to have been a good idea. 

...Something is niggling at Seldan. Something about that the Shadow-Lover said, about - 

- oh! That it had taken an intervention to keep Leareth's soul out of Vkandis' hands.

Brightstar isn't a follower of the Shadow-Lover's god, but the Shadow-Lover didn't actually say that this wasn't done in collaboration with the Star-Eyed, and the timing must have been very finessed. If they'd gotten to Leareth sooner he might have lived, but in that case Vkandis would have Foreseen it and possibly found a way to do something even more wildly destructive. If they'd gotten to Leareth even ninety seconds later, he would have died in the records cache, not in Haven, and the Shadow-Lover might not have been able to grab him. So - it wasn't what Brightstar was trying to accomplish, and he couldn't have known, but it's possible that his decision to help did have some rather important consequences? Seldan isn't sure if this will help Brightstar to hear. 

Honestly Blai does not really want to give Brightstar the advice "keep being stupid in just this way, it seems like it makes you useful for gods who are trying to do stuff and need a stupid person".

Fair enough. 

What does Brightstar want to hear. Seldan is wondering this not because he thinks it's a good idea to tell Brightstar what he wants to hear, it very often isn't, but because it's occurring to him that he genuinely can't tell. It might be best if Brightstar could be convinced to just, you know, do fewer things for a while until he's 25 and has better judgement, but in Seldan's experience, or at least Seldan's vague-common-sense-recollection without any examples of specific cases, it literally never works to give that advice to hotheaded young fools. Blai is really not the right person to, like, say he forgives Brightstar and understands that mistakes happen, or whatever, even if that were the right thing for Brightstar to hear from anyone right now. Maybe Brightstar wants to apologize properly to the people actually close to him, and doesn't know how? 

...Or maybe Brightstar thought of some new insane terrible plan within thirty seconds of the vision, and is now trying very hard to improve on his past choices by actually thinking about whether it's a good idea? He has that sort of fidgetiness to him.