Corax agreed, unsheathing his talons, and together we descended the steps.

At the bottom, the darkness was just as thick and abject. It was like trying to see through pitch. I knew it wasn’t an ordinary absence of light. Our eyes would have penetrated that easily and left us in no doubt as to our surroundings. This was different. Viscous and congealing, here the shadows clung to us like tar. As I stared into the oily depths, I saw the vague adumbration of what appeared to be a coliseum. We were standing back to back in its arena. Beneath our feet were sand and earth.

‘It’s a trap!’ I cried, but too late.

Corax was halfway up the steps when a sliding blast door sealed us in. A step behind him, I turned to face the arena as the unnatural darkness bled away through vents in the floor and a chill I hadn’t realised was affecting me melted from my body. Flaming torches delineated an eight-sided battleground where the skeletal remains of gladiators and their shattered trappings still lingered like unquiet spirits. I recalled where I had seen the antechamber before. It was in Themis, a city of Nocturnian warrior kings who engaged in gladiatorial contest to prove their prowess and choose their next tribal leader. Before each fight, the combatants would wait in barrack rooms to sharpen their blades or their minds before the upcoming contest. Corax and I had done neither. I suddenly wondered what our gaoler had in mind for us.

‘It’s a little archaic, I admit,’ said Curze, our attention drawn to him. He was standing above us, looking down from the pulpit of an amphitheatre. ‘But I think Angron would have appreciated it. A pity he isn’t here to see it. Your paths almost crossed on Isstvan, didn’t they, brother?’

I arched my neck, meeting Curze’s gaze in the highest echelons of the amphitheatre. He was not alone. Thirty of his Atramentar Terminators encircled the arena, the threat of their reaper cannons obvious.

‘A pity oursdid not,’ I replied.

‘You had your chance on Kharaatan and didn’t take it.’

‘You will wish I did when this is over.’

Curze smiled thinly. The two Atramentar flanking him proffered arms, a sword and trident.

‘On Nostramo, we had no grand theatres like this. Our gutters and hives were our arenas, but offerings of bloodsport were plentiful.’

He tossed the sword down to us. It impaled itself in the ground, up to a third of its blade deep.

‘Gang culture ruled our streets and everyone wanted to be a part of the strongest gang.’

The trident followed, striking the earth with enough force to send vibrations all the way down its haft.

‘Even murderers and rapists have ritual,’ Curze went on. ‘Even to scum like them it’s important. Opportunities were always limited, often only enough for one. First thing,’ he said, looking down at Corax, ‘the fight must be fair. Remove your armour, brother. Vulkan stands unequal to it.’

‘I didn’t think you approved of holding court, Konrad,’ I replied, stepping forwards as I challenged him. ‘Isn’t that why you butchered your world’s overlords and spire nobles?’

‘They did not lord over me, nor were they noble,’ Curze uttered darkly. ‘Now, Corax will remove his armour or condemn your own sons to death.’

From the back ranks of the Atramentar, two warriors were brought forwards on opposite sides of the amphitheatre. On one side there was Kravex, my brother’s errant son that he had believed dead; on the other was Nemetor.

Both warriors struggled vainly against their captors, not to escape but rather to make clear their defiance.

‘Nemetor…’ How one wounded son had come to mean so much… Curze had not told me what had become of the rest of my Legion, and I had not the heart to ask him. I believed they still lived, though in what numbers I could not say. Had they perished completely on Isstvan, Curze would not have passed up the opportunity to twist that particular knife. And for all the deception of his trials, Curze had not yet lied to me in anything he had said. The Salamanders yet lived. I yet lived. I had to save Nemetor.

Evidently, Corax had reached the same conclusion and quietly removed his armour until he was standing alongside me in the arena with only the lower mesh of his leggings, greaves and boots. His magnificent war-plate lay discarded on the sand like worthless chaff.

Curze had brought us low, and I felt the gnawing guilt of bringing my brother into this crude pantomime.

‘I am sorry, Corvus. For all of this.’

‘Put it from your mind, Vulkan. I made my decision free of will, as I know you would have done also.’

‘But there is something you don’t understand, brother…’

Two gladiatorial helms thrown in our midst interrupted my confession. One was black, fashioned into the likeness of a bird of prey; the other was dark green and draconian. It was obvious what Curze wanted us to do.

‘Are we to dance next?’ I said, stooping to retrieve the helmet intended for me.

‘In a manner of speaking,’ Curze replied. ‘Put them on.’

The inside of the helmet was rough. It felt heavy.

‘ One lives, one dies,’ said Curze, his voice channelled to me through a reedy vox-link inside my armour. ‘ Gang culture is brutal, brothers. But I wouldn’t expect you to understand that yet. You will.’

I looked up at Nemetor, my son seeming oblivious to his surroundings, then back to Corax, seeing him do the same with Kravex.

I felt the presence of the abyss again, my bare feet teetering on its edge, looking down into hell and darkness. Pain seared my skull from everywhere at once and I realised the helmet was rough because its interior was studded with a host of tiny nails. Curze had just embedded their points in my skull. The abyss throbbed in my mind’s eye, urging me to act, to step off and be lost to its heat.

I fought to stay calm, to rein in the madness threatening to turn me raving.

Corax hadn’t moved yet, though only a few short seconds had lapsed.

‘Survivor goes free, as do his men,’ Curze gave his last edict to us out loud. ‘For let me say now, I have several more drakes and ravens in my rookery. Now, fight.’

Curze had yet to lie to me. If the game was to have meaning, he would tell the truth here too. But I could not kill Corax. I would sacrifice Nemetor for that, though it would hurt me to do so. I would not bow down to barbarism and become like him. Insanity clawed at the edges of my consciousness but I refused to submit to it. Curze would not win. I would not let him.

Corax would defeat me, Nemetor would die, but at least Corvus would live. I could make that sacrifice, I could do that for my brother.

I reached for the sword.

‘ And, Vulkan…’ Curze whispered through the vox-link, a final instruction just for me, ‘ I lied. Beat Corax, render him unconscious or I kill him and his Ravens, letting you watch as I do it.’

I tried to shout out, but a wedge of steel slammed into my open mouth from a device wrought into the helm, muting me.

Corax had yet to move. I wondered if Curze had told him the same thing as me, only the reverse of the scenario I had been presented with.

‘Still reluctant to fight?’ asked Curze. ‘I don’t blame you. It’s a heavy thing to have to kill your brother to survive. But trust me when I tell you that hungry dogs have no loyalty when the prize is survival. I remember a family on Nostramo. Their bonds were tight and they fought tooth and nail for one another, gutting entire gangs that dared raise a hand against them.

‘One winter, one particularlybitter and frigid winter, they went to war with a rival gang. Territory and status were the prize. It became about honour, if you can believe that? Such a lofty and costly ideal. It took them far from what they called home. It was war, only much grubbier than you have ever experienced.

‘Towards the end, food ran short, when the rats were gone and the litter in the streets bereft of sustenance. Desperation breeds desperate men. The loyal gang, the one whose blood ties were so strong… they fell upon each other. Murdered each other. One side wanted to keep fighting, the other just wanted the war to end. You see, brothers, sometimes the enemy is just the person preventing you from getting home.’ Curze stepped forwards, put his hands on the rail in front of him. ‘No more delays. Only one of you is getting out of this. Only one gets to go home.’