Belmarniss will take first watch; she's got an acceptable number of spells, and the bat's caster is likely to come sooner than later and she is somehow the diplomacy specialist in their group.

Tanya is not aware of Belmarniss' opinion that the bat's caster very likely exists and will come soon, or she might have chosen to stay awake.

They take about an hour to show up! Belmarniss nudges Tanya with her foot while she says, "Hey there, like I told your bat we don't want any trouble."

Tanya takes a few seconds to spin up her orb and start casting, but then she lights up the cave and starts flying and creates mirrors around her head for wrap-around vision. Anyone with Detect Magic up will see a Strong Universal aura on her.

She smiles and does not point her gun towards anyone. Who are the visitors?

There's four drow, one with a bat hanging from an appropriate contraption mounted to her shoulder, and an orc. One of the drow startles a little when Tanya casts; Belmarniss says "she just does that when she wakes up," and they calm down a touch.

She also keeps doing that until she goes back to sleep!

Tanya will let Belmarniss talk to them. She's only here in case something goes wrong, so hopefully she won't have to do anything but smile and nod.

There is some silent staring, and then Batdrow says, "Seen here says you're not too scary."

"I imagine something was lost in the translation, what I told it was we weren't looking for trouble."

"What are you on your way up for?"

"I'm a wizard, I wanna do wizard shit, hit a library and stuff. She's a human and wants sunshine for some reason."

"What's got you palling around with a human?"

"Well, you see, she can just do that," gesture, "whenever she wakes up, that's pretty neat, isn't it."

Tanya will continue to let Belmarniss handle the talking and not inquire whether it would help the discussion for her to become more legibly scary. Belmarniss knows she can ask her to do that if she needs to.

"You learning how to do that?"

"Maybe."

"Your human going to make a fuss about our stuff when we march it through?"

"Don't think so. Tanya, you going to make a fuss about their stuff when their stuff walks through here?"

Ugh, slavers. The prosocial thing to do is to disable or kill them, free the slaves, take them back home (i.e. to the surface with them) and get brownie points from the local humans. This doesn't have the normal slave-freeing problems of having nowhere to put them or that the slavers will enslave someone else as substitute, so it's really the best possible situation for freeing them.

However, she hasn't coordinated this with Belmarniss (and can't right now), and shouldn't do this if Belmarniss is strongly opposed. The reputation will attach to Belmarniss as well as Tanya and Belmarniss will want to return home eventually. She might also have other objections that Tanya would appreciate once she heard them. Also, taking responsibility for the freed slaves might involve hard work and/or danger on their way up, and failing to safely escort them back to their homes would reflect poorly on her.

...they can always go back and attack the raiders after they have passed through, if they conclude they should after talking about it in private, and that's probably the winning argument.

"I won't," she confirms. "Don't start any trouble."

"We talking little stuff, big stuff, stuff with feathers...?"

"Struck out on the feathers. Little stuff," shrugs Batdrow.

"Shame, everybody loves stuff with feathers. Better luck next time."

This appears to be enough pleasantries; extremely quiet whispering ensues and the drow pull forward a string of halflings, plus an orc who is apparently trusted not to run off because he's not attached to the string, into the cave, and begin to walk through to the far end, giving the camp plenty of space.

Tanya will be very alert for any sign these drow or anyone who still hasn't come into the cave is going to attack them, take any sudden use of magic as hostile, and otherwise let them pass.

Nope, they're warily watching right back but they have an uneventful quiet shuffle on through the cave, and then they're gone. The halflings don't even entreat them for help.

Tanya waits until their footfalls can't be heard anymore, and then quickly flies a little ways after them to check if they left the bat to eavesdrop.

The orc, not the bat, is bringing up the rear, and looks over his shoulder when he sees the light.

She's not coming after them or going far from the camp at all, she's just checking that they are indeed going on their way and aren't leaving the bat behind.

No bat. Just the orc, who waits to be called before advancing into the next chamber.

Alright. She flies back to Belmarniss.

"We can free the slaves and return them to their homes. It would be the prosocial thing to do, disincentivize raiding and slavery, and gain us goodwill on the surface. However, even if we kill all the slavers word might eventually get back to Noctimar about your involvement, and this would be a problem if you return home. And they might be difficult to protect on the way up, and slow us down, but on the flip side they know the way up and will have seen any other people we're likely to meet, so it's likely a net advantage in those terms. What do you think?"

"They keep halflings as slaves upstairs too. If they were trading in humans you'd have some amount of a point."

...oh. 

It's good for Tanya, personally, if the humans upstairs limit their slavery and other objectionable practices to halflings and other non-human races. It's still bad and wrong but she can't do anything to change a whole slave-owning society (except try to sell them on the rational virtues of capitalism and cooperation). And she can't do anything for these particular slaves either so she can put them out of her mind.

"That makes sense, if you strongly expect that they were slaves on the surface, and can't and wouldn't want to be brought back up and set free without further help. Are all halflings in Taldor enslaved?"

"There are plausibly free ones but those'd be more of a hassle to get ahold of and train and there's no real commensurate price increase unless you can convince some gullible buyer that you have on your hands a genuine halfling princess and you can just as well bullshit about one who was a slave when you got them. If they got somebody free it was by sheer accident."

That makes sense. "What about the orc? He didn't seem to be enslaved."

"No, he was. Just isn't new and they don't think he's a flight risk."

Oh well. "Then there's nothing we can do." And Tanya can go back to sleep, after waiting a little longer just in case.

Yup. Belmarniss'll wait for her to wake on her own.