It’s one of a couple of standard options, yeah. The pay’s a lot better if you are part of the actual command structure, but a lot of spellcasters value their independence or have other competing formal commitments and it’s worth working with them anyway. - and for Alfirin the pay is, uh, nominal. Taldor cannot afford ‘all the spells every day of an archmage and her routinely getting into fights with Tar-Baphon personally’. 

Is she getting non-pay compensation or doing this out of the goodness of her heart?

Goodness of her heart. Well, and a look at Arazni’s spellbook and the opportunity to hit ninth circle in the first place but at this point pretty obviously the only thing keeping her here is that she wants the Crusade to succeed.

They assume nobody else has hit ninth circle on crusade? How many eighth-circle wizards do they have?

Caida makes a face, because that’s not at all a question you answer offhand for spies, except Iomedae did say that they were allowed to know everything her staff was allowed to know. 

“One in the army at eighth, one adventuring on a contract, one retired who’ll do buffs, and now of course the prisoner. Four full-time at seventh and half a dozen with some kind of arrangement where they’re helpful at least occasionally.”

(That is so many. The spies let it show on their faces because De Luna's letting it show on his.)

And Tar-Baphon has... fewer? As many? More powerful spellcasters?

Oh, significantly more. Five or six at eighth, more than a dozen at seventh. When he wants to cast ninth circle spells he has to show up himself, and he's reluctant to, but they're outgunned for sheer spellcasting capacity and have been since Arazni died and arguably even while they had her. 

How do they compensate for having so many fewer spellcasters?

Well, Iomedae can take literally anyone, Tar-Baphon included, possibly up to an actual Duke of Hell, down in a round, and they do come back but not immediately, and lose their items for good, and when it's important she can also talk the High Priests of other faiths into working with them and get some ninth circle cleric support alongside the ninth circle wizard support, and they have been steadily accumulating magic items that let them stretch their spellcasters farther, and also Iomedae just - things don't go wrong when she's around. They say gods can nudge fate.

How much are they relying on Iomedae specifically there, or do they have enough powerful nonspellcasters that the enemy spellcasters have to be cautious for that reason?

They have a lot of powerful nonspellcasters who the enemy cannot afford to allow to get near them. Most of the Shining Crusade command has been fighting for thirty years and is only slightly less dangerous. Paladins have some serious advantages at lich-killing, obviously, but it's not as if Arnisant can't do it when he gets a chance.

They rely on Iomedae specifically for the - things going miraculously better than they would be expected to. Everyone else is a very experienced very courageous very deadly fighter but no one else is going to be a god.

How long have they known that Iomedae will be a god?

That's a good question. Caida thinks it has gotten....steadily more obvious over the years, and she herself started acknowledging it openly in the last ten. One time a few years back he asked her if she would take a secret to her grave and she said very seriously that she would take it to the Starstone.

...was her interlocutor reassured by that?

Well, honestly it's a little less reassuring than the normal version but she's a paladin, right, she's not going to say something that's more reassuring but less true.

Well, obviously not, but - it kind of implies that she's not planning to keep it secret after ascending, and they would expect someone asking her to keep a secret to also be asking her to keep it post-ascension - though they suppose asking for someone to take a secret "to their grave" is already a pretty weird request as far as secret-keeping goes.

Iomedae is extremely reluctant to make commitments binding on god-Iomedae lest, you know, some god that'll be unable to manipulate her as a god sets out to try to do it in advance while she's still a human.

Wise of her, they suppose. They can imagine this makes some people correspondingly less willing to share secrets with Iomedae, though.

Maybe? It's not as if god Iomedae can't be expected to still care about the Good and exercise good judgment and desire that those who trusted her not be disadvantaged thereby. God Iomedae's going to care about all of that, even more perfectly than mortal Iomedae. She just can't afford to be bound in any respects where mortal Iomedae was wrongly guessing what approximated Lawful Good in a specific case. 

He is at this point vaguely self-conscious about how ridiculous 'my commander, who is going to be a god' must sound to people who don't stay up on the news about this. Presumably even in whatever backwater of Taldor where the language is spoken like this the broad strokes are known.

Lastwall's spies will continue to ask questions of Caida as if they were foreigners with no context or prior knowledge of the Crusade and no particular interests. (Their actual interests being "What, actually, is Alfirin's deal" and "What other Alfirin-sized gaps are there in the historical record")

Caida has been told to tell these people lots of things so he will, somewhat uncomfortably because lots of them are not in fact public things.

The Shining Crusade has been, on the whole, reasonably accurately depicted in the holy books of the faith of its goddess, with the one glaring omission aside. His impression of Alfirin's deal is that she is a very admirable person who has spent her life in the service of the Shining Crusade. ...he has heard the claim that she and Iomedae were, before they became too important for frivolity, lovers, but won't repeat it; he hasn't verified it. He thinks Iomedae's judgment is to a first approximation perfect and she trusts Alfirin. Alfirin doesn't, in fact, try all that hard to not be parsed as Evil but that is different from actually working against the interests of the forces of Good.

When they've talked for about half the day Iomedae's available for a brief meeting with Lastwall's advisors.

They are available at her request, of course! Does she want all four of them?

She wants the intelligence officers. (She separately expects some fascinating conversations with her military advisor but that's slightly less time sensitive, and she doesn't want to make her poor staff field the spies all day.) 

She will say straightforwardly that she's sure they aim to notice if there's anything here surprising to Lastwall, that she prefers they have the resources to succeed at that - and that it's somewhat in tension with her own best use of them, which is in Barstoi, where they're now running either a decoy offensive or a real one and where they have very little in the way of preexisting resources (a list of names they're in correspondence with openly or secretly, some not-likely-reliable maps, some soldiers from the region, that's it) so it's not even much disadvantage to be from another world. 

They are happy to help in Barstoi, De Luna and Falkner will still be here to notice things surprising to Lastwall. Also it seems reasonably likely that Rumblebrand should stay here too, depending on what they can learn from the soldiers from the region - supposedly-itinerant dwarves tend to stand out more than supposedly-itinerant humans. Are any of the soldiers from Barstoi spellcasters who can share language?

Not without someone giving them imbue with spell ability, but someone can so they should be all set. Rumblebrand if he wishes can be Grand Polymorphed to be not a dwarf though it's permitted to decline that as some people find it profoundly uncomfortable; if he wants it he should decide today so Alfirin can mask the spell as she casts it; the Polymorph will of course be until it's removed but the masking will endure a month or so. It's also worth a permanent Telepathic Bond if this is expected to be a reasonably long-standing working relationship; she'll tell them who to get the Bond with and who to have cast it. 

And then she can give them all her (sparse) available intelligence on Barstoi. Do they have any questions for her.