He paused by a series of raised compression pipes, the metal hot to the touch and dripping with condensate. His warriors were moving into position, ready to assault the blockhouse, and he took a moment to glance over the angled parapet at the roof’s edge.

The city stretched out around him, its metal-skinned towers and gleaming silos shining like silver beneath the beating sun. The Ultramarines quickly formed a perimeter as the gunship lifted off in a howl of engines that sounded like its namesake, and Remus watched as it peeled away, moving into formation with two-dozen others. Rippling beams of light lashed up from the ground towards the aircraft. Concealed batteries flayed the sky and half a dozen Thunderhawks were struck, each one falling out of formation and describing sinuous arcs towards the ground.

Remus didn’t watch them fall, but pressed on towards the blockhouse mounted in the centre of the roof. Its door was armoured and no doubt sealed, but it would present no challenge to his assault team. No orders needed to be given. He had briefed his warriors prior to dust-off, and each man was aware of his role. Not only that, but following the prescriptions of the primarch’s great work, each man knew the role of every one of his brothers. Should any man fall, another of his brothers could take up his responsibilities.

He moved forwards at speed, his bolter pulled tight into his shoulder. He could hear the sounds of fighting coming from other buildings: the sharp bangs of bolters and the whoosh-roarof enemy flame units. Remus felt his lip curl in a sneer. Such weapons might scare xenos forces, but held little fear for warriors armoured in the finest battle-plate forged by the weapon-masters of Macragge.

Sergeant Archo and Brother Pilera ran to the armoured door. With practiced swiftness they rigged the hinges and lock with krak charges. Det-cord unspooled from their gauntlets as they took position to either side. At a nod from Remus, a silent data-squirt blew the charges and the door bulged inwards, as though struck by an invisible fist of colossal dimensions. Remus and Barkha ran forwards and thundered their boots against the door. The metal buckled, folded nearly in two by the awesome force.

The twisted door toppled inwards, and before it had landed, another two Ultramarines hurled a handful of grenades through the smoking hole. Rippling detonations, curiously muted, like a string of firecrackers, echoed up from below. Barkha stepped towards the ruined frame, but Remus held up a fist, holding his warriors in place.

A liquid jet of flame roiled up from within the blockhouse, bellowing with seething power as it licked up the stairs beyond the door. The blaze erupted from the door, but before the weapon could fire again, Remus nodded to Barkha. His sergeant swung around the door and loosed a barrage of bolter fire on full auto down the stairs. The noise was deafening, the booming reports echoing madly around the interior of the stairwell and lighting it with strobing flashes.

Barkha pounded down the stairs and his squad followed him down. Remus led the second squad down, as Sergeant Archo formed his warriors behind him. The interior of the stairwell was blackened and scorched, like the flue of a volcano.

Should make the bastards feel right at home, thought Remus.

He emerged from the stairs into a wide cloister that ran around the inner faces of the structure. The building itself was a hollow rectangle with an interior courtyard, fifty metres wide and a hundred long. Gunfire snapped and banged from below, the enemy desperately trying to reorganise and realign their defences. Remus saw three command tanks – two Rhinos and a Land Raider – each with a forest of whip antenna bristling on its topside. The armoured vehicles were painted a drab green with black draconic heads embossed on their side doors.

‘Archo, sweep left, Barkha, go right!’ he shouted.

The words were unnecessary; both men knew exactly what to do. They had read the primarch’s treatise on such storming actions, and needed no input from him. Green-armoured warriors emerged from chambers further along the cloister, guns levelled, but they were already too late.

The Ultramarines filled the space with shots, putting down such a weight of fire that even artificer-crafted battle-plate couldn’t withstand it for long. Remus fired his bolter on the move, compensating for the additional weight on the underside of his barrel. He automatically braced his shoulders for recoil, before remembering there was no need. The two warriors before him fell back, one toppling over the balustrade into the courtyard below, the other dropping with altogether less theatrics.

Remus knelt beside the body, studying the armour and its iconography. Jagged-toothed dragons emblazoned upon fields of fire combined with hammer and forge symbols to create an earthy, Promethean feel. Too feral, too cultishto be Imperial. It had the look of a savage culture raised up to civilisation, but which would never really be civilised.

Salamanders. Even the name sounded barbarous. A Legion named for the legendary fire-breathing monsters of a forgotten age. The name had no gravitas, and Remus shook his head at its primitive, visceral nature.

‘How does it feel to die knowing you are my enemy?’ Remus asked the fallen Salamander.

‘No different than when I died as your brother,’ said the warrior, before his head rolled to the side.

Remus nodded, and paid the warrior no more attention.

His visor changed to display the tactical situation. His warriors had swept through the upper reaches of the building, and were fighting their way to the lower level. The suddenness of their assault had caught the Salamanders off-guard, but there was still some fight left in these fire-loving cultists. Remus matched the ongoing status of the fight into his perfect recall of the primarch’s works, and immediately saw how they were going to break the defences open.

‘Sergeants,’ said Remus. ‘The north stair is ready to fall. Archo, I want your squad on the south cloister. Lay down suppressing fire on those tanks and the warriors in the courtyard. Barkha, you and I will break in through the north while Archo keeps their heads down.’

‘Understood,’ said Sergeant Archo. ‘Moving into position now.’

Remus led his men around the cloister. Flames jetted up from below, and here and there grenades clattered as they looped over the parapet. Ultramarines hurled them back, but the Salamanders soon learned to hang on to their explosives before hurling them. Remus kept his head down as a cluster of grenades burst against a wall further along from him. Two of his warriors went down, their armour shrieking as they fell. He felt the enormous pressure wave roll over him, but it wasn’t enough to put him out of the fight.

‘On!’ he cried. ‘Up and forward!’

The Ultramarines rose and bolted for the stairs. Remus saw Barkha’s men opposite, and rolled around the corner to see the forward elements of his squad pouring fire down the stairwell. Barkha rounded the corner of the opposite cloister at the same time, and both men took up position at the top of the stairs.

‘Resistance?’ asked Remus.

‘Minimal, easily dealt with,’ was the terse reply.

‘Assault in, three, two one…’

Almost exactly on cue, a volley of heavy gunfire erupted on the far cloister. The chugging bark of heavy bolters filled the courtyard, followed straight after by the swooshinghiss of missiles. The fire up the stairwell slackened almost immediately. Remus spun around the corner and took the stairs down to the courtyard two at a time. A Salamander appeared at the opening below, the archway sparking with coruscating residue of the specially modified missile warheads. He levelled a meltagun at Remus, but a shot from Barkha took him in the head and punched him out of sight. Another Salamander fired his weapon around the archway without exposing himself, but the shots were wild. Remus’s armour registered an impact on his right shoulder, but the strike was glancing, and wasn’t nearly powerful enough to stop his charge.