A shadow crossed Magnus’ face, as though Ahriman’s question had strayed into a region he disliked.

“Because this in an epochal moment for humanity,” he said, “a time when great change is upon us. Such times require to be marked in the race memory of the species. Who among us will ever experience a moment like this again?”

Ahriman was forced to agree with that sentiment, but as they drew near to the first checkpoint in the perimeter around the Emperor’s dais, he realised that Magnus had neatly diverted his question.

A pair of Warlord Titans stood sentinel on the approaches to the sheared root of the mountain. Clad in gold and bearing the thunderbolt and lightning motif of the Emperor, the Titans had come from Terra to protect their lord and master. His mightiest praetorians, these titanic custodians were the perfect blend of technology and martial spirit.

“Bigger than the one you have propped up outside the Pyrae temple,” said Hathor Maat to Khalophis as they marched between the engines.

“That they are,” agreed Khalophis, missing or ignoring Maat’s mocking tone, “but war isn’t always won by the warrior with the biggest gun. Canis Vertexis a predator, and would take both these fine fellows with it before it went down. Size is all very well, but experience, that’s what counts, and Canis Vertexearned its fair share on Coriovallum.”

“We all did,” agreed Phosis T’kar sagely. “But when you talk about Canis Vertex, don’t you mean it wasa predator.”

“We’ll see,” said Khalophis with a grin.

“A Titan wouldn’t worry me,” said Hathor Maat. “It’s just a machine, a big one, I’ll grant you, but without a princeps to command it, a Titan is simply a giant statue. For all their skill, the Mechanicum haven’t yet invented a machine that doesn’t need a human being to control it. I could agitate the water molecules in the princeps’ skull until his head exploded, boil the blood in his veins or send millions of volts through its carapace to electrocute the crew.”

“I could bring it down easily enough,” said Phosis T’kar playfully. “I did it once before, remember?”

“Yes,” said Uthizzar. “We all remember. You never tire of telling us how you saved the primarch from a Titan on Aghoru.”

“Exactly,” said Phosis T’kar. “After all, the bigger they are—”

“The bigger mess they make of you when they tread on you,” finished Ahriman. “We are here to escort the primarch, not indulge your fantasies of how powerful you are.”

Beyond the Titans, hulking golden warriors in the armour of the Custodes protected every approach to the hub of the continent, giant warriors of equal aspect to the Astartes, with plates of brazen gold, inscribed with curling script, bedecked with fluttering oath papers secured with wax seals. Six of them manned the checkpoint, with a trio of Land Raiders growling behind them and a pair of dreadnoughts to further augment their strength.

“First Titans, now this. You think they expect trouble?” asked Hathor Maat with a smile.

“Always,” said Ahriman.

“Surely these security measures are ridiculously overblown and unnecessary? After all, who would dare attempt something hostile on a world crowded with Astartes and the best war machines the Imperium has at its disposal?”

“Have you ever met a Custodes?” asked Phosis T’kar.

“No, what has that got to do with anything?”

“If you had, you would know how stupid that question is.”

“I met one on Terra before setting out for Prospero,” said Ahriman, “a young, ramrod-straight warrior named Valdor. I believe the primarch knows him.”

Magnus grunted, telling them everything they needed to know about thatacquaintance.

“What was he like?” asked Uthizzar.

“Can’t you tell?” asked Hathor Maat. “What’s the matter, don’t you read minds anymore?”

Uthizzar ignored the Captain of the 3rd Fellowship, and Ahriman smiled as Magnus turned to face his officers with a mock-serious expression.

“Enough,” said Magnus. “Captains or not, you will not be permitted to pass onwards if the Custodes decide you are not of a serious enough mindset. Their word is absolute, and not even a primarch can go against it in matters of the Emperor’s safety.”

“Come on, Ahzek,” pressed Hathor Maat. “What was this Valdor like?”

Magnus nodded indulgently, and Ahriman said, “He was a grimly efficient praetorian, if rather humourless. I suppose when you are part of the cadre responsible for the safety of the greatest being in the galaxy, there is little room for levity.”

“Little?” said a voice appearing at Ahriman’s side. “There is no room whatsoever.”

HOW THE CUSTODES had come upon Magnus and the Sekhmet, Ahriman could not fathom.

He had not sensed their nearness or caught the faintest tremor in the aether of their presence. One minute they had been approaching the checkpoint, the next, their Tutelaries had vanished in the blink of an eye and two Custodes warriors were alongside them.

They were tall, as tall as the Astartes, though their armour was nowhere near as bulky. It had a ceremonial look to it, but Ahriman knew that was a misleading interpretation, one calculated to give the warriors encased within the advantage. So like Astartes and yet so different, like distantly-related kin gone their separate ways and evolved into new forms.

They held long Guardian Spears, lethal polearms that could cut through sheet steel with ease and could sever the ogre-like body of an armoured greenskin in two with a single blow. Red horsehair plumes spilled from their tapered helmets like waterfalls of blood, and the green glow of their helmet lenses was eerily similar to that of the Thousand Sons. Gilded carvings snaked from the seals of their neck plates, curling around their shoulders and down the inner facings of their breastplates.

“Halt and be recognised,” said the warrior who had spoken before, and Ahriman focussed all his attention on him. He could sense nothing, not even an echo of his presence in the world, as though he were as insubstantial as a hologram. Ahriman’s throat felt dry, and an unpleasantly bitter aftertaste flooded his mouth.

Untouchables,said a voice in his mind with a familiar flavour, powerful, but not powerful enough.

Ahriman could not see them, but with the knowledge that there were psychic nulls nearby, he found he could identify them by their very lack of presence.

“Six of them,” he said over his armour’s suit-vox.

“Seven,” corrected Magnus. “One is more subtle than her compatriots in veiling her presence.”

The Custodes crossed their spears, barring their path to the Emperor’s dais, and Ahriman’s anger flared at the insult implied by the presence of the untouchables. Magnus stood before the Custodes, his physique imposing and threatening, his crested helmet a larger version of those belonging to the warriors before him. For an instant, it looked as though Magnus was one of them, a towering golden-armoured warrior lord.

Magnus leaned down, his eye tracing a path over the inscriptions that flowed across the burnished golden plates of the leftmost warrior.

“Amon Tauromach Xiagaze Lepron Cairn Hedrossa,” said Magnus. “I would go on, but the rest of your name is hidden within the curve of your armour. And Haedo Venator Urdesh Zhujiajiao Fane Marovia Trajen. Fine names indeed, displaying grand heritage and exceptional lineage, but then I would expect nothing less of Constantin’s warriors. How is the old man these days?”

“Lord Valdor abides,” said the warrior that Magnus had identified as Amon.

“I expect he does,” said Magnus, reaching out to touch the beginning of the spiralling script on Amon’s shoulder. “You have an old name, Amon, a proud name. It is a name borne by my equerry, a student of poetry and the hidden nature of things. If the name maketh the man, does that mean you are a similar student of the unknown?”