(It's not his only precaution!  What makes Carissa's side hard is that she's the one who has to actually not die.  He can explode himself and come back again to find more sensible Efreet.)

Anyways!  By a similar token, Carissa Sevar has sometimes been known to undergo great cognitive shifts when under importantly different cognitive conditions.  Perhaps at INT 29 she will decide she is a different person not bound by past oaths.  Perhaps at INT 29 she can configure her thoughts in a way that sidesteps the geas earring without that ever looking on a first step like a forbidden intent to defeat the geas.

It would take both Intelligence and arrogance to imagine you'd come up with a plan to defeat that possibility at INT 27, to raise up a more powerful Carissa and then contain her.  It would require more than just believing in your own Intelligence's power; it would require respecting your own INT 27 but not her forthcoming INT 29.  It requires thinking that you exhaustively searched every option Carissa Sevar would see, using not just a more powerful INT 29 but also her own different ways of thinking.

You could call the alternative Wisdom, but in dath ilan they'd just call it thinkoomph or maybe security mindset.

Carissa totally bets at INT 29 she'll be able to think of a way to betray Keltham. Maybe even one that leaves her options more appealing than pleading with Otolmens to squish him. 

She'll take off her beautiful wonderful headband and replace it with an Intelligence headband while she gets Wisdom, and then take it off entirely while she gets Intelligence.

One after another, the five Malik cast five Wishes upon her, using the exact wordings that she gave them and bound them to with oaths, that she be made forever Wiser.  The five Wish spells are differently worded in the sequence, to match at some invisible edges, to tile to a greater Wish spell that settles into Carissa and makes her something more.  If there was a sixth possible spell in this sequence, it has been lost, and gods are forbidden to return the knowledge to mortals.

It is, in fact, doing something a little different than the headband. 

She likes it, whatever it is. She imagined at some Wisdom level she'd be able to comprehend Keltham's attitude towards enhancement, if not agree with it, but she suspects now she'll never share it. The more she is, the more of her there is, the better; she is moving towards herself.

Next, then.

Finding the next target goes faster now that they've realized they're looking for huge buildings and businesses of many nobles, which will incidentally advertise Wish-sequences as sidelines.

The next such building makes Foresight prickle against her mind like it can no longer do in Golarion where prophecy is broken; she instantly Dimension Doors them out.

The one after that doesn't feel dangerous. 

Five Intelligence, please.

These fucking rich people.  These Golarion-filtered shops could only even offer Foresight scrolls for sale because somebody sold them to the City of Brass centuries earlier, before prophecy broke.

Anyways, yes, it continues to be more complicated than that, but five Intelligence, sure.

It doesn't make anything new click into place; it wouldn't be expected to, until she puts the headband back on.

...how about five Splendour, then.

Splendour!

Among the many complicated feelings Carissa has, as she continues on her shopping spree, is a sense of intense grief that she cannot enjoy it; that this is a beautiful thing, a fascinating thing, an incredible thing, something she wants to extend to every person alive and every person ever to live, and yet all she can feel is terror that it won't be enough, that no matter how intelligent she gets she won't see a way out.

She gets strength and dexterity and constitution enhanced, too. There are cognitive effects, which she expected, and they're not subtle, which surprises her. Humans are, it turns out, a body as much as a soul, and having that body respond more quickly to your instructions, move more effortlessly, have more energy, is like the difference between being struck with a flu and being in perfect health. 

(If she figured out an assembly-line setup for belts of Constitution, no one would ever get sick....no, doesn't matter, they're all going to get annihilated...)

She wants her headband back. She wants to know if her despair is an error or just correct. She wants to put her head in Carmin's lap and cry. 

"You done?" she says to Tarnish, more irritably than Tarnish, who hasn't done anything wrong besides being the kind of loathsome person who wants to destroy the world, deserves.

Keltham asked Tarnish under Detect Thoughts and also truthspell, if she was confident that her commitment to do Literally Anything in exchange for some mortal finally holding Pharasma to any kind of account, would stand up to increasing her own Intelligence, Wisdom, or even Splendour.

Tarnish's reply, which in its own way revealed more wisdom than many who detect as Wiser, was approximately, 'lol no how could I possibly know that'.

She's fine waiting on all cognitive enhancement until later, and is just here for Strength, Dexterity, and Constitution boosts.

They can head back, now, though it would also be okay if Carissa wanted to shop around more and buy more amazing magical items that Tarnish can watch her not enjoy.

Or even magic items that might help Carissa in not destroying the world, if she's got any ideas for that.  Tarnish is not very against destroying the world, but she does have dreams of her own: she wants the world to be fixed, in part by her own deeds and acts.  That way she can go around ever after being awful to Good people, and then telling them she's done more Good than they'll ever do, and she wants them to suck it up and take it in partial repayment.

They can do a second trip later if she thinks of anything. She doesn't, actually, think that saving the world is going to involve clever overpowered magic items; just the people with the power to kill everyone deciding that actually they should only destroy Hell or something.

He does worry that they won't be able to make a second trip, the City of Brass being too interested, by then, in the question of whether those mysterious visitors Actually Had That Many Diamonds, especially if they hear from Golarion about who that probably was and the concept of 'chemistry'.

But then, he also worries about that because he is still on the lookout for 'tropes', and it would be tropey if they only got to make one trip and had to buy everything they needed on that one trip or else fail.

"Let's windowshop in the slave markets for a bit and then head home."

"Hey, bitch?  I don't mind destroying the world but I do slightly prefer it get fixed instead, and I don't trust Keltham to actually achieve that while he's trying hard not to think about it as a possibility.  I'm definitely not smart enough to do it myself.  And you won't be smart enough either, if you stop hoping.  So buy literally whatever it takes to cheer you the fuck up, we've still got shopping money and I'll approve spending another five Wish diamonds if I have to."

To her own astonishment Carissa feels something, then. It's a surge of fury and loathing and terror stronger than she's ever felt before and, wow, it is not helping at all.

"Of course Keltham isn't going to think of it. He's a fundamentally despicable person from a broken and nightmarish world which treats actual human values - the desire to live, the desire to endure, the desire to grow - as horrible dangers everyone must be carefully twisted out of contemplating."

"He is broken in a way that no enhancement can repair, because they are twisted so as to ensure every bit of humanity remaining in them is lost in favor of the broken blankness of their civilization when they get smarter. He will not come up with anything. He is fundamentally not the kind of mind that could come up with anything."

She would not be saying this if she had her headband on, because it's not even quite true, it's a sideways articulation of a thought she did need to think but can and should sit on until she can say it better, and she knows it, but it turns out one of her enhancements or some combination of them, or maybe some other feature of the situation, maybe just the adrenaline from all these high-stakes magic negotiations, gave her stronger emotions, and suddenly Tarnish is rather too much to bear.

"Whoever he might have been, if he'd been born in a better place, if he'd been born in a place with humans, he strangled it and replaced it with what he calls 'dath ilan' and which is blank emptiness opposed to everything that humans are. At least he understood enough to grieve it. If anything goes well, if anything goes less than maximally badly, it'll have to be because I think of it. And I'm not going to think of it without the headband on, which means it's bottlenecked on the-disembodied-spirit-of-Darkness-and-betrayal-and-horror my boyfriend gave himself over to thinking about whether It can trust me with that.

The idiot running this project thinks we only get one trip because of tropes. I don't know how he decides which tropes to take seriously but I'm going to come back here once I have my headband on and a concrete plan, because tropes could just as easily have meant we got ambushed on this trip, or ambushed on this trip unless it was only the first of many, or we could have been ambushed while I was out cult-encouraging, tropes are not actually narrowly enough understood we can evade them like that.

You are right, though, that I should do whatever cheers me up, which is going to the slave markets and fantasizing about how if I'd listened to Asmodeus when he told me to be Eviller, I could have, when I realized what Keltham was planning, leveraged that to squish him like the blot upon humanity he is and conquered Golarion and lived happily ever after for all eternity and everyone else would be better off too."

Her heart is pounding like she just fought several Worldwound demons. 

"Some of that was probably incorrect," she says, slightly more calmly.

"Who cares?  Not me, that's for sure.  I liked it."

"I'd help with the slave market appreciation but I vastly overstretched my innate abilities by trying to cheer you up literally at all."

His own shopping trip is both easier and harder than Carissa's.

Easier, because he doesn't fear death that much; he found ways beforehand to verify that he seemed to have a soul.  (Casting Magic Jar from scroll, for example, and wasn't that an interesting experience.) 

Harder, because Ri-Dul cannot accompany him into the real negotiations; and by himself he doesn't look, doesn't feel dangerous the way Carissa does, even with his own Hellwrought lesser-artifact headband.  With Mind Blank up they can't read him and don't know him for a wizard below third circle; but 25 Splendour and Glibness is not quite enough for a dath ilani to fake being dangerous.  At least, dangerous in a way that things like Efreet understand.

Noble Efreet try harder to take advantage of what looks weak; he has to negotiate harder and longer to arrive at acceptable prices, and they are still unreasonable compared to Sevar's.

...He doesn't try all that hard to avoid being taken advantage of.  None of this, from beginning to end, is a fair trade.  He's doing it in the City of Brass, and not some other place with noble genies, because the Efreet have a reputation as hard and unfair bargainers.

He carries about himself a briefcase he had made.  He has made much smaller pellets of the contents that he can use to demonstrate, if they don't just believe his word that, yes, he can make entirely nonmagical explosions that would be dangerous even to beings of Fire if scaled.  Do they press him, he will consume all about himself in fury and destroy his trade goods alongside his attackers.  He will come back from that.  They won't.

The noble Efreet do call him coward and weakling, and try to goad him about it.

He's at 27 Int and 23 Splendour, even to start.  The Efreet are dumber than Keltham was when he first arrived in Golarion.

He cannot improvise true talk-control, that takes neuroscience he doesn't have and can't infer that quickly without doing experiments, for he's not a god as yet.  But the Efreet feel to him more like mechanisms than people.  Dangerous mechanisms, imperfectly predictable, not navigable to arbitrary outcomes as a talk-controller could manage; but not, really, people, except in the sense of having qualia.

He patiently negotiates their conversation graphs and pathways through time at minimum risk to himself.  As is, of course, still some risk; but he's arranged for the 'risky' outcome to still be acceptable and that's not really that much risk.

"Be warned that I'm having some trouble figuring out exactly what you're trying to accomplish here, in terms of decoding the false message you're trying to send somebody.  Whoever you're trying to confuse by it is going to end up very confused except in the extraordinarily improbable case that they are smarter than myself."

Ri-Dul does not look to him like only a dangerous mechanism.

He treads carefully, here.

"Your guess?  I may not confirm or deny, even if you say it, but I want to know."

"You had me send out feelers for smaller diamonds, too small for Limited Wishes and too ugly for jewels, and wished to make it appear plausible that you were purchasing those in larger quantities than you actually were.  Your negotiating rules here are designed to make it look possible that you are spending more Wish diamonds than exist in all Golarion to be bought."

"If I had to guess, it would be that you desire Cheliax to believe that you have a chemical method for aggregating small diamonds into larger ones."