You coloured at that, and protested, “My God—”

“And you shouldn’t call me God either,” he said. “You don’t comprehend the word, and I don’t want to be God to you yet. You’re an invalid, not a disciple. Listen to me. Can you do that? I hate to push you, Harrowhark, but we have so little time.”

This was not to be borne. “I still maintain some of my faculties, Lord.”

“Well, that’s all anyone can hope for,” he said.

You propped yourself up against the coffin that did not contain Coronabeth Tridentarius, as it was a heavy slab that couldn’t be hurt by your leaning on it. The sword was making your back ache. The Kindly Prince watched you try to stand, your shoulders bowing beneath the steel, and then he said: “Harrow, we’re still just outside the Dominicus system. Once you’re better, we will send the Erebos to the Ninth House, and it will deliver what I said to you it would deliver. Then it will go from House to House to give them back their dead—but I won’t be on it. You can choose to part ways with me. Or you can come with me as my Hand. In a real sense, it’s up to you.”

You tried to remember what you had said when you had first woken up aboard the Erebos; what you had said when first faced with your Resurrector. But you couldn’t. “I chose—”

“In ignorance,” he said. “It was no choice. Listen.”

He went to half-lean against the bulkhead closest to the plain coffin, put his tablet atop it, and let his hand rest upon the unadorned surface quite close to the little rose. The Emperor said, “Harrowhark, what happens when somebody dies?”

It was a crèche question. You ought to have been able to answer it in the same way other people walked or breathed, which was why you found it difficult. The simplicity seemed a trap. You dug your thumbnail into the top of your thigh until it squelched all the capillaries beneath the skin, and you said: “Apopneumatism. The spirit is forced from their body. The initial thanergy bloom occurs.”

“Why?”

“Thalergetic decay causes cellular death,” you said carefully, pressing the nail in harder, “which emits thanergy. The massive cell death that follows apopneumatism causes a thanergetic cascade, though the first bloom fades and the thanergy stabilises within thirty to sixty seconds.”

“What happens to the soul?”

“In the case of gradual death—senescence, illness … certain other forms—transition is automatic and straightforward. The soul is pulled into the River by liminal osmosis. In cases of apopneumatic shock, where death is sudden and violent, the energy burst can be sufficient to countermand osmotic pressure and leave the soul temporarily isolated. Whence we gain the ghost, and the revenant.”

“And what has a soul?”

You weren’t going to last the distance. The questions were beginning to sound stupid, or sophistic. The Body watched you with careful, filmy eyes. “Anything with a thalergetic complexity significant enough to … have a soul. So, humanity.”

The Emperor drummed his fingertips atop the plain coffin, and he said, a little whimsically: “Why have we not an immortal soul? I would give gladly all the hundreds of years that I have to live, to be a human being only for one day.”

This threw you utterly. “I— Pardon?”

“Harrowhark, think,” he said, which reminded you very unwelcomely of someone. You gave your thumbnail a better edge, sharpened the dead keratin to a point, and finally drew blood. “What else has an enormously complex mass of thalergy? What’s the role of a Cohort necromancer?”

Your brain bowed out disgracefully, but something of the old Harrowhark remained, enough to stand there and ask questions. You were grateful for your impertinent ghost-self to ask: What was the role of a Cohort necromancer? Better to ask the purpose of a Cohort swordswoman: to support the necromancer, to provide the death and the thanergy to begin the cycle for necromantic magic to work. Foreign planets were never thanergy planets; they possessed dilute thanergy, of course, but fundamentally they were thalergenic in character. Send a necromancer down there and she would be largely useless. Thanergy really came from—

More to the Body than to him, you said: “A planet’s a ball of dust. Its thalergy comes from the accumulation of microbial life. You can’t consider it one coherent system.”

“Call it a communal soul,” said her Emperor. “What’s a human being, other than a sack of microbial life? You’re a bone adept, aren’t you? Flesh magicians are exposed to this idea of a system earlier than in your school.” This was kindly, even humourously said, but you still found that you immediately wanted to be tossed out the airlock at the idea that your aptitude made you less than a flesh magician: someone whose entire education was in the carnal. Experts in things that were yellow, and wobbled. People who thought there was something really interesting to be found in meat.

He mistook your deeply bigoted hate for disbelief, and said: “Just accept the proposition for now that a planet has an enormous single amount of thalergy. If this thalergy is converted, what might happen during that transition?”

“We already know what happens,” you said. Your tongue was growing thick in your mouth, and your eyelids were sore and swollen from wanting to close. The first rush of adrenaline had run its course. The Body came and took your wrist in her hand and ringed her fingers around your bones, quite tightly. This let you say: “The Cohort prepares a planet for necromancy every time they have to breach it. Over time, with the introduction of thanergetic decay, the planet converts. Necromancy proceeds as normal afterward. Nothing happens … plant and animal life both change, of course … and eventually the planet flips totally and the population has to be moved, but that’s such a long-term process that it takes generations. You can’t quantify it as something happening.”

“Now kill the planet all at once,” said her Emperor. “What then?”

You looked at him. The Emperor of the Nine Houses raised his hands, palms up, as though offering a helpless prayer to the roof of the cargo hold. His alien eyes were cool and calm. You knew of only one mass dying-off of planets.

So you said: “You tell me, Lord. You were there for the Resurrection.”

“Yes,” he said. “And I saw the thalergy convert immediately. The difference between dying of illness and dying from murder. An enormous shock, the immediate expulsion of the soul. And just as when a soul is ripped untimely from a human being, when a soul is so rudely taken from a planet—”

Sweat came to the centres of your palms totally unbidden. A trickle of blood started down your leg, and you stopped it in midflow, dried it to flakes on your skin, and clotted the breach. Such an act took no effort now.

“A revenant,” you said.

“Always a revenant,” he said. “Every single time, a goddamned revenant. Pardon the pun.”

You fancied you could see the Body breathing, her chest rising very slightly, in and out. The Emperor crossed his arms and stared across the cargo hold, his face lit from beneath by electric lighting, the gleam in his eyes black and wet. You caught him moistening his lips with the tip of his tongue.

“We called them Resurrection Beasts,” he said.

It took him another moment to continue, and when he did, it was with the air of a man telling a very old story. “When the system died … when I was younger, those ten thousand years ago, and I brought us back from that brink—all those revenants scuttled off to the farthest parts of the universe, as the soul runs from its corpse in the blind first fear of transition. I have never seen a planet make another in the same way; I’ve seen lesser monsters—minor Beasts—but nothing, nothing, like that first wave.

“Harrowhark, those revenants move through the universe, inexorably, without pause … and they feed on thalergenic planets as they go, like vampires … and they won’t stop until I and the Nine Houses are dead. They have had me on the run for a myriad, and they’re nearly impossible to take down.”

This made very little impact on you. It had the dim and nonsensical ring of a fairy story. You said, “The Lyctors have died … fighting these things?”

“Fighting them?” said God. “Harrow, I’ve lost half my Lyctors distracting them. They’re hideously complex to destroy. The ones we’ve killed, we killed through luck—they were young, and we were at full power—and then … once our numbers thinned out … by sheer accident, or by suicide mission.”

“How many revenants are there?”

You prepared for an astronomical number. The Body raised its eyebrows when the Emperor Undying said, “Three.