"Okay, let's do that."  Them having a totally innocuous Detect Intelligence spell they can exhibit to him undoes some of the earlier updates that formed his previous prior about Conspiracy, around 3x worth of it, if real.

"Carissa, according to you, is it usually possible to take a spell that'd ordinarily be powerful, and cast it in a weaker way that would deceive somebody about how easy it was to make their save against that?"

" - huh. You know, I've never heard of anyone doing that, but it's got to be possible in theory, because dumber wizards generally have easier saves, and if nothing else you could curse yourself to prepare and cast the spell while substantially stupider, and given that that would work it's presumably possible to figure out what the dumber wizards are doing wrong and do it wrong on purpose. Though I think that'd be harder than it sounds, because we're talking about muscle memory, right, trained instincts for how to build a spell.

It also wouldn't work if the target had substantial experience with spells, because they could just notice the spell seemed sloppy."

"Well, at least they're doing a good job of pretending that Ferrer isn't as good at perspective-taking-of-ignorance as Asmodia and that the different branches of Conspiracy aren't in ongoing communication."

"New obviously magical earrings, Carissa?"  He performs Detect Magic as he speaks.

"Present I made you. Or made myself for you. I finished them up yesterday. They cast Geas on the wearer, the sixth-circle magical command spell, I thought it'd be fun. You're now going to declare this suspiciously coincidental timing which I suppose it is, in favor of - Conspiracies that didn't realize you were doing anything weird today until after you saw me, or that need me to be wearing magical obedience earrings - do you want me to take them off -"

"...I hate to ruin a sex surprise, but earrings of mind control sure are a thing I suspiciously cannot test on myself.  There was going to be some amount of plan spoilage from today somehow, I guess, if I'm asking Cheliax to spend giant amounts of money I should be willing to spend at least a little - go ahead and tell me what the earrings putatively do, we can send Asmodia out first if you like."

"I would mildly prefer that."

"I'll go get in some quick updates of my Conspiracy while Keltham's not looking.  He'll never think to suddenly check on me if I say that I've thought of that, causing him to think it's a waste of time."

"Thank you, Sevar, your plot to cause Keltham to give me these crucial two minutes by forging magical earrings will not be wasted."

"Changed my mind, I would prefer Asmodia staying to Keltham dashing out to check on her in the middle of me explaining my sex toy."

"Actually - I will close my eyes, and stick my fingers in my ears and hum to myself while you talk quietly.  That works if it's not classified information."

She suits actions to words, and rests her brain while she hums.

((It's the most stressful day of her second life and she'd still take it over any day of her entire first life.))

"Proceed while Asmodia sends her telepathic messages.  Oh hey you have a short word for that."

"If we're important conspirators we definitely have Telepathic Bond up, which is why I suggested an antimagic field to you. The earrings are command-word activated like the handcuffs, and then treat the controlling party's orders as magically compelled, as the spell Geas. - I invented it from scratch. I thought it'd be fun to try inventing my own magic items."

This is false!! It's less false than it was an hour ago; she's been making some modifications on the fly. If she gets enough undistracted time, then by evening it will probably be true. It means the earrings succeed at their original concept but are less obviously targeted at that.

She fucking loves this headband.

"That is the most Carissa sex toy ever."

"I'll try it out sometime when I won't have to wonder if the effect is real."

It doesn't even occur to him to activate the supposed effect on Carissa and question her; the Conspiracy wouldn't make earrings like that, if that would work for him.

Tragic. They could have had a sexy interrogation scene. 

"You okay with... rephrase.  This is your brief chance to argue me out of my holding on to those earrings, just in case they're vital Conspiracy-maintenance equipment."

"Go ahead. However, later, once this is over, you have to be very impressed with me about them or I won't invent any ludicrously expensive magic sex toy surprises for you again."

"I doubt I can properly appreciate it until I've got better Spellcraft.  But I'll be duly impressed that you're probably not supposed to be able to make sixth-circle items at fourth-circle, that you got access to what sounds like heavily forbidden mind control magic for purposes of a sex game, and with your general pervertedness levels."

"- if I'm holding the earrings does the effect apply to me."

"No! I'd have warned you! Also, you can simply not say" Message  'equestrian pumpkins', "which isn't really the kind of thing people say much by accident!"

This sequence of events seems predictable.

Maybe too predictable.

There could be rules about how he has to accept the bearer-controlling mind-control magic item voluntarily or knowingly; they could be suspicious that his Spellcraft has advanced enough to recognize what a mind-control item looks like.

"Apologies to Ordinary Carissa.  Remove the earrings from your head, but keep them yourself."

"Yes, Keltham." 

She obeys.

Great, she'll get to keep working on them. That went perfectly.

Asmodia, booped by Keltham, will duly open her eyes and cease her humming.

"Request quiet while I rest my brain for a few minutes, until Maillol's scry people get here.  Possibly afterwards too, if we don't have to talk much to them."

"Some point in the next hour, unpredictably to me, tell me to go to the bathroom?"

"Check."