On the northern side of the Urgall Depression, a fresh sea made ready to sweep in and carry all of the mortal debris away.

Across from the muster field of the Salamanders, which was little more than a laager of drop-ships, were the Iron Warriors. Armoured in steel-grey with black-and-yellow chevrons, the IV Legion looked stark and stern. They had erected a barricade, the armoured bastions of their own landing craft alloyed together, to bolster the northern face of the slope. Great cannons were raised aloft behind it, their snouts pointing to the ash-smothered sky. A line of battle tanks sat in front, bearing the grim icon of a metal-helmeted skull. And in front of that, Iron Warriors arrayed in their cohorts, thousands strong. They held their silence and their weapons across their bodies, with no more life than automatons.

The drop-zone was flooded with warriors now, as a makeshift camp materialised to serve the injured and secure the bodies of the dead. Tank yards manifested as labour teams of Techmarines and servitors assembled to make standing repairs. Multiple triage stations were being set up in the lee of the larger Stormbirds, whilst the holds of some Thunderhawks acted as emergency infirmaries. The able-bodied looked to their armour and weapons. Quartermasters took stock, replenished ammunition and materiel where they could. Officers reorganised in the face of casualties. Subalterns and equerries gave brief reports to line officers, and standard bearers acted as rally points as the entire Vexillarius was put into motion organising for the second assault.

Not a single legionary about the XVIII stood idle.

Yet the Iron Warriors, the entire muster on the northern slope, neither spoke nor moved beyond what was necessary to assemble.

Chief Apothecary Sen’garees voxed through to the command echelon, including Vulkan and the Pyre Guard, complaining of the lack of reply regarding requests for aid, specifically medical.

Numeon felt a grim silence descend across the whole Urgall Depression like when a storm eclipses the sun, as he saw Captain Ral’stan of the Firedrakes raise his fist in salute to their iron allies.

Not one responded to his hail. Only the wind kicking at their banners gave any sense of animus to the IV Legion throng.

‘Why do they ignore us?’ asked Leodrakk openly.

Vulkan was staring in the direction of his brother, Perturabo. The Lord of Iron returned the Lord of Drakes’ gimlet gaze with one of his own.

‘Because we are betrayed…’ said Vulkan, disbelieving, horror turning to anger on his face, ‘To arms!’

More than ten thousand guns answered, the weapons of their allies turned on them with traitorous intent.

CHAPTER TWENTY-FIVE

Reunited

‘Though the battle had ended and the enemy was far from the reach of our blades, most of us didn’t come back from the Urgall Depression. Even those men who escaped, those pitiful few, even they didn’t come back. They’re still there now. We all are, fighting for our lives.’

– unknown legionary survivor of the Isstvan V massacre

It looked bad. There was no other way to describe it. Definitely bad. Nurth was bad, but this was a whole other pit of groxshit that Grammaticus had found himself in. And then there was the alien. Not Slau Dha, or Gahet. Certainly not anyone affiliated with the Cabal. Here was a different player entirely, an eldar whose agenda was as inscrutable as his identity.

And then there was Oll.

But he couldn’t worry about that now. He’d done everything he could on that front, and as much as his old friend had clearly resented being reached out to, what other choice did Grammaticus have?

The universe suddenly felt very small, and Grammaticus was somehow at its beating heart and under intense scrutiny from all interested parties. Insects on microscope slides had more privacy. He thought of Anatol Hive, and wished that he had been allowed to die in the Unification Wars.

Fate had other plans for him, though. If asked at the time, he doubted he would have said that that fate included a battered group of legionaries and running for his life down a sewer tunnel. If they knew of his true mission…

His two minders looked tired, and fraught. The one called Leodrakk, the Salamander, had eyed him several times since they had reached what Grammaticus assumed was a rendezvous point. He also assumed that whoever Leodrakk was meant to be rendezvousing with was late. This would be Numeon, his captain and the legionary in charge. It didn’t bode well. What boded worse was if Numeon was dead. That left Leodrakk running things, and he looked about ready to charge to his glorious death, killing Grammaticus into the bargain. Not that it would matter, but then his mission would effectively be over. He also feared to imagine what the Word Bearers would do to him.

He didn’t know what the Salamanders and their allies in the other broken Legions had intended to achieve here on Traoris. Whatever it was, it had gone awry, and he suspected that he carried some weight of blame in that.

Leodrakk’s eyes told him all of this. They spoke of grief and a dangerously fatalistic desire for revenge. Grammaticus had seen men like that in the united armies, when they were fighting Narthan Dume. He’d never seen it in a Space Marine before, and he wondered just what these warriors had lost to transform them so egregiously.

‘What are you staring at?’ snarled the Salamander. He was crouching down, and had been looking at his helmet, facing him on his lap.

‘I’m wondering what happened to you,’ said Grammaticus.

‘War happened to us,’ he replied curtly.

‘You are made for war. There is more to it than that.’

Leodrakk looked into the stinking filth that streamed beneath their feet, but found no answers in the dirty water.

Instead, the Librarian spoke up.

‘We were betrayed,’ he rasped, ‘at Isstvan. It was worse than atrocity. The massacre we endured was only the physical manifestation of our collective trauma. The real pain was to come, and it was a malady of the mind. Not everyone survived it.’

Hriak, the Raven Guard, paused as if trying to see into Grammaticus’s mind for the source of his curiosity. It was deeply unsettling, and Grammaticus fought to keep his hand from trembling. Many years ago he believed that a very close friend of his had succumbed to a psyker’s mental intrusion. It was all lies, of course. Everything about it had been a lie, one way or another. It had still unnerved him, though, the sheer destructive potential of battle psykers. No wonder the Emperor had removed them from the Legions.

‘From the horror of Isstvan, we escaped aboard a drop-ship,’ Hriak continued, ‘but the horror did not end there. All of us were changed by what we had witnessed, the sight of our brothers slain in droves beside us, our former allies turning their guns on our backs while at the same time known traitors to our fronts opened up with their weapons in vicious concert.’

Grammaticus looked askance at Leodrakk for a reaction as Hriak related their story, and found him to be deeply uncomfortable at the retelling, but content to let it go on.

‘Some of the survivors aboard our drop-ship were not themselves,’ said Hriak. ‘When a man is heightened to a certain point of battle fervour, it can be difficult for him to come down from that. Sometimes, if the experience is particularly traumatic, he can never fully recover and a part of him will always be at war, in that self-same conflict. Such men, blinded by this trauma, have killed in error, believing friends to be foes. It takes a great deal for the Legiones Astartes to succumb to such a trauma. Our minds are much stronger than ordinary mortals, but it is possible.’

And then Grammaticus knew. He knew how Hriak had sustained the wound to his neck, the one that had very nearly slit his throat completely. It wasn’t actually on Isstvan that he’d received it, it was on the drop-ship. It was inflicted by–