Well, that's interesting.

The Yeerks report to their superiors. They poke the souls to make sure that this won't be a telltale problem-of-some-kind, poking them through the host to whom they belong. They make sure they can use all the soul powers.

Sehana Daeredh's soul has a major passive shielding effect that protects him and anyone he touches against all sorts of things, not including the stun effect the Yeerks got him with but including most kinds of bodily harm and mind-affecting magic. He, or a Yeerk working through him, can extend the effect into a green-glowing aura with a radius of about six feet, but it takes serious concentration. His active soul powers are minor telekinesis and the ability to make sounds louder or quieter within about ten feet of him; both are Yeerk-accessible.

Tyela's soul has a teleportation power which only recently extended to work between dimensions. Her Yeerk can operate it as well as she can. Her soul also gives her a perfect memory and enhanced vision, which her Yeerk can access just as well as she does, although the Yeerk does not get a perfect memory of its own just from inhabiting her. She doesn't see quite as well as an Elf, but it's close.

Daeredh keeps himself entertained by imagining all the possible ways this unexpected development could lead to the world being doomed. It's not hard to think of a few. If the Yeerks took Emperor Esarkan, they'd have Nuime, and the Emperor's security arrangements take into account the fact that he considers assassination a form of peaceful protest. (Emperor Esarkan is very immortal.)

Tyela's chosen coping mechanism, once she gets past her initial panic, is to remember all the facts about rocks that she knows. She knows so, so many facts about rocks.

Well, this is promising. If the peal is chasing them then having magic powers the peal doesn't know to expect is pretty important.

The Yeerks send the King a courtesy notification and Issiak puts together a small strike force with which to collect Emperor Esarkan. The fact that the souls world knows of a Flat Arda complicates matters - osanwë does Yeerk detection - but should be possible to work around.

Some peaceful protestors with stunners and little sloshy containers make their way to Emperor Esarkan.

Emperor Esarkan does have security.

Emperor Esarkan's security is not prepared for stunners.

He is mildly surprised when the peaceful protestors break into his office. He is just as susceptible to stunning as everyone else they've encountered so far.

When he opens his eyes, he isn't the one opening them, or the one sitting up, and he definitely isn't the one making eye contact with the Elves lurking in his office. Presumably there's some conversation going on there but he is not party to it.

If he could operate his body, it would be laughing.

I suggest you surrender immediately, he thinks in the direction of whoever is trying to conquer his empire.

Oh? says someone.

If you start doing this sort of thing to my subjects, I'm going to be increasingly annoyed with you. I can afford to be forgiving, but my mercy is not infinite. I have no idea of your numbers or your capabilities besides what you have demonstrated to me, but I will be very, very surprised if anything you've got can hold up against Dawn-shining Taliar.

He can guess that they've got the scouts - he should've sent Nezhefena; Nezhefena would've been safe - and he's pretty sure they got this notion from Sehana Daeredh's tendency to catastrophize. Well, as a counterbalance, he can point out to them that Elaneth-imire Kazaryne Taliar swats gods like flies. If these people want to try capturing Taliar, they are welcome to do so. Esarkan expects to be highly entertained by Taliar's account of their defeat.

If his occupant is nervous, it doesn't display that to Esarkan in any way.

That's all right. Esarkan is very patient. He can wait for them to surrender or be destroyed, whichever comes first.

His soul's powers are almost universally passive; the immortality takes up most of it, and the rest is a sort of general sense of how his empire is doing, with an attentional boost that lets him keep track of it all. When his occupant doesn't respond further immediately, he turns his attention to contemplating the input from that sense. He is completely unworried.

The Yeerks want soulbearers. Soulbearers will make everything else easier.

Esarkan has pretty good wherewithal to collect them and the Yeerks can whisk them away to be stunned and infested.

This works for the first fourteen soulbearers they try.

And then the fifteenth one wakes up just like the rest, and screams internally much like the rest, and is promptly engulfed in white-hot flames, which is new and different. The Yeerk pool where this operation is being conducted is vaporized in the blast. Outlying buildings are scattered across the countryside in molten flaming pieces. For twenty miles in every direction, the heat cooks birds in the sky and fuses soil into glass.

The Kandrona generator range is not actually that big. That's all the pools and all the Yeerks in them at the moment boiled away. There's still the ship tank with the vegetation supply, and anyone who was in a host and farther away than that; that's all. They scramble to figure out what happened; they send someone to summon the baby daeva-Yeerk casualties; they send the King word -

He hops over to somewhere within Elf-sight of her but well outside the apparent radius. He's also outside osanwë-range, inconveniently. He watches her anxiously. There's that other habitable planet to teleport her to if she looks likely to blow up his kingdom.

There is presumably a soulbearer somewhere inside that enormous white fireball. It shrinks slowly; molten glass begins to cool at the edges, pingpingping.

And then, abruptly and without warning, a lightning-fast lance of flame darts out toward the King, obliterating everything in its path. It's a mere sixty feet in diameter, so there will at least be less collateral damage on this one.

They don't have Yeerk spellbinders to make people indestructible yet; this is fatal.

If there is anyone left with teleportation capabilities, they might want to do something about the giant fireball rolling across the landscape at a human's walking pace—

—oh, never mind, looks like someone already did.

"...Nezhefena?" asks the fireball.

"Please cool off so I can reunite you with your husband," says Nezhefena. "If you melt this island I don't have another one lined up."

The flames dissipate. Aeleva stands at the center of a crater. Nezhefena is next to her, untouched by the heat. "...I suppose I can trust you," she says. "Your soul wouldn't let - whatever that was - happen to you, would it."

"Corino sent me to figure out where all the disappearing soulbearers were going. Can you shed any light on that?"

"I didn't know soulbearers were disappearing until they disappeared me. They must've got Esarkan. They do something to make you fall unconscious, and then - I woke up and something was controlling my body - and that fucking—"

Her son chooses that moment to contact her.

Hey, is now a good time for a visit?

Your husband has been kidnapping soulbearers, she says, and sends him the memories - waking up a prisoner in her own body, blasting everything in range, inhabiting the fire of her soul and finally seeing him show up to watch. If you want to resurrect him and ask why, I won't stop you.