Okay fine he's dead.

About 300 halflings are running towards locations across the south-east quarter of the city. It's at most a 1.5 mile trip, for those travelling the furthest to Trick alley or the other side of the Sorrowgate.

Unrelatedly, several thousand halflings and humans are running in various directions to get home before dark. It's a busy city.

The ones with the most distant targets left first, but they're not perfectly coordinated and the explosions will be spread out over about two minutes.

Can you organise a response to this situation within two minutes?

We can inform our superiors that there's a situation within two minutes, if we spend them running in a straight line towards the Midnight Temple.

We can stop ... twenty of them, before they get to a target.

Many of the guards who stop them will be smart enough not to read the envelop.

A lot of Cheliax is made of stone. All of the important buildings at least.

The temporary stuff not so much. The slums definitely not, and they were closest to the source and so the halflings targetting them had shorter distances to run.

Even with an explosion to start it, and the sort of weak accelerant you can buy in bulk and keep in a supply room for a good moment, a lot of the fires will fail to develop.

Still, there's a lot of buildings on fire.

The guard will focus on the strategically important government buildings, the warehouses owned by rich merchants who can pay them to care, and anything owned by a politically connected person with a relative involved in deciding promotions.

And Estrella and her spawns will meet up again, back in the sewer system.

They're not really expecting any thralls to make it back to where they started alive, but if they do good for them.

The runners will reach her about when the smell of smoke reaches her about when it gets serious enough for a wizard to spend a dim-door and a fly to get to her quicker.

Even before she hears reports of the use of Dominate Person on a massive scale, she's assuming it's enemy action. It's the start of a war.

She'll order they wake the rest of the guard, divert units from around the city, and form a cordon around Whipcrack.

She'll order an evacuation of the cordon, and that the commoners be led through the southern gates. They'll have to spend the night outside the walls, if they don't have a home inside them. With this many dominates, it's likely there's a vampire on the loose, so anyone without a home or a good will save is a liability.

Spot fires can be attacked with water, by buckets or by spells.
They'll use poles and ropes to intentionally collapse smaller buildings in advance, to make firebreaks and because flattened rubble doesn't burn as well.
They're not going to be fast enough to demolish the whole slum faster than the fire can consume it.

She'll authorize a Control Weather scroll to bring torrential rain, though it'll take ten minutes to do it.

Prophecy is broken, so of course she saves a commune for the last few minutes before a war, in case her god only learns something then that implies a change of plan.

She gets enough questions to narrow it down.

They should still go ahead with the invasion, but there will be an attack on Egorian on the same night, and that she ought stay behind to stop it.

The problem with using slaves for all your plans is that I can see you do it, idiot.

If you want to have slaves that's valid. You just have to do it under Me.

You can't just say "We're locking you outside because there's a vampire, and we don't want you getting dominated where you can start more fires", there'd be a panic.

They'll say it's because the city has a curfew and they have to follow their own rules, or because they want to investigate who was responsible and they might interfere with evidence, or because if this is some foolish halfling uprising they aren't letting them have even a chance, or because screw you that's why.

Nevertheless, many who fled with none of their few possessions will find themselves curling up in some alleyway somewhere, crying pathetically.

Many who didn't flee fast enough will already be dead, before any chance of a magically induced rainstorm saving them.

A few minutes after the fires have started, there's no longer direct sunlight at street level.

With her spawn back in their bag and having already snuck past the cordon, she'll emerge onto the surface and run away from the fires like everybody else.

Anyone who wants to talk to her can have a Dominate Person and an envelope for urgent delivery: run up to someone organising the response to the blaze and read it out to them, just don't look at the letter until you've found someone who needs to hear it, because it's written with a magical ink that disappears ten seconds after you start reading it to prevent messengers peeking at important letters.

How dumb do you think we are?

Your beautiful mistress commands that you don't think about it too hard.

Oh, is that a family hiding in an alley because it's not safe outside the city and they can't get home? Would they like some Dominate Persons too?

Internal communication is quick enough that she'll learn of more spot fires appearing in the rest of the city, tracing a path but still not beyond the 2-mile radius of the Control Weather already being prepared.

Whoever's behind this isn't content to burn the slums. Cheliax wouldn't really care if somebody burnt the slums. They want to burn everything and the slums are just the most flammable starting place.

She'll direct more clerics to move north and fix the other spot fires, and she'll authorize a second Control Weather scroll for the north of the city to ensure coverage, but hold off on starting to cast it until it seems necessary.

What's the motive?
To disrupt the war effort by causing as much damage as cheaply as possible, obviously.

Are they Good?
They're targetting civilians first and foremost, so probably not. Maybe the follows of Ragathiel are hardcore enough to make this kind of attack, but they'd want it to at least build up to something better.

She'll get detailed enough reports beaten out of former thralls to know that there's at least six spawn, almost certainly enslaved to a master vampire. 7 Mind Blanks is prohibitively expsensive for most possible enemies, she'll order divinations on the vampire and her minions to hunt then down.

Attempts to scry her will fail.
Attempts to scry her spawn will usually fail, if you can't beat nondetection and a +5.
If it succeeds you'll see that they're packed close together inside a very tiny extradimensional space.
Locate Person will fail, it doesn't work if the target is on a different plane.

We can use the scry to target a Teleport
It's a different plane.

We can use the scry to target a Plane Shift
You need a tuning fork.

We can use the scry to target a Gate
If this is any of a large number of traps she might end up very strongly regretting that, and there's no guarantee the master is with her spawn, and it's still possible all of this is just to make her waste a ninth-circle spell slot.

She'll try to track them by more ordinary means, she'll call an inquisitor and send out low-level devils, imps and hellhounds mostly, starting from wherever the most recent victims report a sighting.

They are with her, but not in a way that's useful. They're in a Bag of Holding in her Bag of Holding. The nested extra-dimensional spaces make the inner bag inaccessible, so there's no way to get to her from them until she takes the inner bag out.

She can pick out a victim or two a minute, though the actual numbers of fires she starts isn't super important.

A massive stormcloud has been steadily forming above the skies for ten minutes now, over a suspiciously circular area covering most of Egorian.

It glows a terrible red in the last dying glows of the sunset, and the reflected light of the fires below.

They finish casting the Control Weather.
The first drops of rain are ready to fall.

Stristyko is pretty sure he can't and doesn't sleep. He was just resting.

Stristyko rose from his rest much earlier than you'd think because, being a busy lich with much to do, he wears a ring of sustenance solely for the reduction in required resting time. Or maybe being a lich is like having a ring or sustenance on already? One of those two. The rules aren't completely clear at all on spellcasting undead rest requirements.

They are clear that he can't prepare more spells until tomorrow, and that probably means midnight, right?

Yeah, sure, midnight. Let's go with that.
And you still have to wear a ring of sustenance if you want to get spells tomorrow after only a two hour rest.

Great. Even though he's already awoken, he'll stick to using the current days spell slots until he can prepare more after midnight.

He'll start by fetching the 30 Burning Skeletons that he already owns and controls, having created them through Animate Dead (4th).

They're each wearing an amulet around their necks, with a copper disc depicting an Explosive Rune.

Being mindless undead, they of course can't read it themselves, though being immune to fire damage it wouldn't hurt them if they did.

He'll march them into his Bag of Holding, and then spend the tedious hour it takes to cast an ordinary Scry (4th), on another of the unimportant Egorian natives that Estrella's taken hairs from.

As he casts it, he'll think about how he's never worked up the courage to ask Estrella if she poops. She drinks blood all the time, it's got to go somewhere, doesn't it?

The scry target is a middle-class merchant, watching the fires with his family through a window from his apartment above their store, because as long as his shop in particular doesn't seem threatened it's not his problem.

He's wondering how much he can justify raising prices in response to whatever shortages this will doubtless generate.