The Count does not seem particularly inclined to name a specific favor; if pressed, he will imply that he would prefer it if his life contained rather less marching around in unpleasant conditions and rather more socializing with the Mendevian elite, though of course he understands there's only so much the Knight-Commander can do.

The Mendevian books or the Lastwall handbook books? 

The amended Lastwall handbook that Blai acceded to on the advice of Mendevians.

...Well, it depends on how they interpret Lastwall's rules about mitigating circumstances. The regulations of the Lastwall handbook certainly allow for the death penalty for being a cultist of an Evil god, and his advisors would generally assume that this counts, but the handbook doesn't seem to make an explicit distinction between Urgathoa and an actual demon lord, even though (as far as the Mendevians are concerned) demon lords and similar are much worse than any other type of Evil god. With his amendments that... might be downgraded to just sending them all to the Condemned? But they're not sure whether this counts as "Good intentions" (since it's good when people don't get sick), or whether they're supposed to treat all but one of them as acting "On advice," and they can't agree on the "Character" or "Likely avoidance of future offenses" criteria.

(Some of his advisors think these are basically a bunch of harmless superstitious fools who just need to have it explained to them that 'praying to Urgathoa to not get sick' is not a good idea, but others of them think that anyone who's going around secretly praying to Evil powers is probably bad news. Also, several of them keep tripping over themselves to apologize for their ignorance of his foreign ways and explain that they mean no disrespect.)

"The most important form of respect is respect for my time. Spend less of it on apologies."

He goes down the list of mitigating circumstances. Are they young morons? First offenders?

Some of them are young. None of them have been caught at this or anything similar before, though presumably this was not their literal first time ever praying to Urgathoa in this manner.

He is inclined to send them to the Condemned but since they wanted to experiment with Ember's redemption-detection-power can she maybe talk to them before they're assigned there?

"I can talk to them, but I don't know how well it'll work if you'll send them to the Condemned no matter what."

"If you would like, I would be happy to provide my proposals for experiments to test her powers, as you requested! I prepared several, due to my anticipation that you would find several of them unsatisfactory, even though they would be more informative about the efficacy of her powers."

"What've you got, Nenio?"

"My first proposal is the following: ask bird girl to interview all criminals that you have successfully apprehended and predict what they will do if released. Next, release them, making no special effort to prevent them from committing further crimes, and observe whether they in fact commit more crimes. This will allow you to determine whether those that bird girl identifies as unlikely to commit more crimes are indeed unlikely to do so, as well as whether those she identifies as likely to commit more crimes in fact do so at comparatively elevated rates, in order to distinguish between the hypotheses 'bird girl's identifications are accurate' and 'few criminals reoffend'. However, I predict that you will disprefer that option due to your predictions about the likely consequences of releasing all criminals."

Nenio does, as promised, have several other proposals prepared, such as:

• Release only the people bird girl identifies as unlikely to reoffend, which is low-risk if bird girl in fact has some sort of unusual ability to identify repentant criminals but high-risk otherwise. To mitigate the risk, Nenio proposes terminating the experiment early if the reoffense rate is high.
• Have bird girl attempt to use her powers exclusively on those who would not otherwise be executed, give them the punishment they would typically receive, and similarly compare the rates of reoffending. Nenio is less confident that this will be informative; it won't provide any information on particularly serious crimes, the greater supervision present in the Condemned might affect the reoffense rate unequally across different groups, and bird girl's assertion when asked about this proposal was "It's not exactly like that. Sometimes I can tell what someone needs in order to stop hurting people, but if they don't get it they might keep hurting people." (Nenio considers this comment to be a potential limiting factor on many related proposals, such as having bird girl assess exclusively those sent to the Condemned and not those who received more lenient punishments.)
• Pick some smaller subset of one of the above populations, so that if bird girl does not have any sort of ability along these lines the consequences will be more limited.
• Locate someone else with extraordinary powers, such as Nefreti Clepati (one of the greatest spellcasters of the modern day, despite the fact that she's a cleric, and rumored to be all-knowing, mad, or both), and compare their assessment of whether someone will reoffend to Ember's.

(She also has various proposals for how to ensure the accuracy of the reoffense rate beyond simple observation, ranging from 'put them under an Abadar's Truthtelling to ask if they've committed any further crimes' (which might have the side effect of reducing crime rates after the first time, which would be quite unfortunate for her ability to gather useful data) to 'have butterfly boy's butterfly spy' to various forms of arcane divination magic.)

Right, so, Blai's idea here is a lot like that second bullet point but he acknowledges the drawbacks. .......these people might actually make a fine test case for something riskier, though. Unempowered prayers to Urgathoa are really not something you want happening around you especially when there is already a disease outbreak but they're not that dangerous and it would also be pretty hard to check up on them with the conventional Condemned supervision methods (it seems awfully burdensome to check if each one has cleaned his plate, let alone done it without privately contemplating how gluttonous that is in a reversal of their prior practice) and relatively easier with the higher-scrutiny measures he can justify if it's an experiment.

The question is whether it's Lawful. "Become a subject of Nenio's experiments" is not on the books as a consequence for consorting with unallied powers of the Lower Planes and this doesn't seem like some grave omission of the books. He's going to pray about that for a bit.

Okay so. Punishments have several functions. Deterring recidivism - that being the subject of the experiment. Preventing recidivism, in those who may not be deterred. Deterring imitation - that requires that they look aversive to onlookers, though he is getting the sense that how concerning things look to onlookers varies quite a lot culturally, but also this one unfolds into why it's desirable that punishments be predictable in advance, for the benefit of those onlookers who do not happen to show up to each trial and every flogging. When possible, as with the entire conceit of the Condemned, extracting some compensatory use out of the malefactor. Using Ember's advice to sort the Urgathoans into - what, "Condemned" and "let off with a warning" - fails very badly on the second account, but he did just notice that "let off with a warning, but subject to experimental followup" is not actually worse at discovering recidivism than is "put in the Condemned under a commander who probably has a lot to deal with already" and may also not be worse at prevention. So the main disadvantage of letting some of them go on Ember's advice is that... this will not look scary to third parties...

.........he can probably figure out how to make it look scary.

"I am willing to use Ember's advice to sort the Urgathoans into Condemned she expects may recidivize and reducing the sentences of the others to a dressing-down I conduct myself, if this seems agreeable to her and you," he tells Nenio. "With associated followup, of course."

That seems very sad for the people who still end up in the Condemned, but it's good that he's willing to give some people a second chance.

"I think I can do that," she says solemnly. ".......Is it always illegal to pray to Evil gods?"

"There are carveouts for Asmodeanism in Chelish allied forces."

"Oh. ...Sometimes I pray to them to ask them to stop hurting people. I didn't know that was against the rules."

"It is an understandable impulse" if not one that has literally ever occurred to him in his entire life "but one reason to avoid praying to Evil entities is that it gives them more visibility into what's going on. This is acceptable when it's Asmodeus, in this particular environment, because we can presume Him committed to holding the Wound, though it wouldn't be somewhere more removed from that concern; it's an unnecessary intelligence leak in other cases. If Urgathoa knows more about who is sick and how this is affecting things around those people then She can act more cheaply, and do more Evil."

She looks visibly upset by this! 

"I'm really sorry, I didn't know I was making it easier for them to hurt people."

"Maybe that should be the next topic I talk about while we're marching, I don't know how widely understood it is."

"Perhaps I can conduct a survey of your troops before you do so! However, I am uncertain whether people will be willing to answer honestly, which might decrease the usefulness of my results."

"It might, yes."

While Ember is talking to the Urgathoans he will conduct a walk-and-talk about this topic!

His soldiers seem much clearer than Ember on the topic of "you should not pray to Evil gods," or at least the ones who aren't clear on that aren't admitting to it, but their understanding of why they shouldn't pray to Evil gods is somewhat... mixed. 

"Gods get stronger when you pray to them, that's what makes some gods stronger than others."

 "So do you spend all your time on the march praying to Iomedae?"

"...Well, no, but if I did it would be a good thing."

"Praying to Evil gods is bad because it's Evil, praying to Good gods is good because it's Good."

"I don't care why they say they're doing it, it's probably just an excuse to justify being a demon cultist. If you ask me the best thing to do is string them up."

"Praying to a god makes you more like that god, no matter what it is you're saying. That's why Iomedae was able to ascend, you know."

"If you're loyal enough to one god, it's easy for them to bring your soul to them when you die. So you shouldn't risk praying to an Evil god, you might go to an Evil afterlife even if you're a Good person."

 "No way that's how it works, if that were true you could go around robbing people blind and still end up in Elysium if you do it drunk."

"That works fine if you're actually loyal to the Drunk. But most robbers throw in with the Thief sooner or later."

"—huh, if what you're saying is true, wouldn't that mean it's really dangerous to leave captured cultists alive, even if it's only for a little while? I get that it would be better if they repented, but it doesn't really seem like it's worth it."

Honestly he can't rule out all of these theories, but he thinks the "visibility to the enemy" angle is an important one. It is not a huge emergency if a captured cultist has a little time to think about their choices because the information they have should already be extremely limited, coming as it does from inside of a jail setup.

"If you take them in a fight they might have information about your forces, your tactics..."

 "They could just pray anyways once they get to the Abyss."

"They might also pray mid-fight, you cannot close off this avenue of information short of killing them in ambush before they know you're there. Which, of course, you should do if it's convenient but cannot always arrange."

He thinks for a couple moments. "If we can force them to distract themselves praying in the middle of a fight that's probably still helpful?"

  "Maybe if we got the Sarenrites to lie to the cultist prisoners they'd give wrong information to their gods."

   "Are Sarenrites even allowed to lie? I thought they had... something about sunlight and truth."

  "I think it depends on whether they're Lawful?"