Vulkan snarled.

The witch was trying to even the odds with sorcery.

He tore his arm free but further serpentine bonds coiled around it, pinning him. Vulkan roared and the beast roared with him, sensing its meal was close. Widening its chasmal jaw, the pteradon was about to bite off Vulkan’s head when it reared up in sudden agony. Swinging its leathery neck to peer over its shoulder, it screeched at a second assailant.

“Like I said, worry about yourself, brother…”

Ferrus Manus appeared from behind the monster, seen through the gaps between its massive limbs. He’d shattered a bone framing its wing membrane and leapt clear as it slashed at him belatedly with its tail. Shedding the root bonds, Vulkan punched Thunderheadinto the beast’s unprotected belly. Muscles ruptured and bones cracked, eliciting another shrill of bestial agony. A swipe of the pteradon’s bladed wing claw prevented his follow up attack and forced him to retreat, while Ferrus Manus was kept at bay with stabbing thrusts of the monster’s barbed tail.

Venturing in close again, Vulkan took a chunk of scale from its back. The two-handed blow left gore drooling between the knots and scars of its body like before, and he knew its formidable strength was ebbing.

“We’re close!” he yelled.

Ferrus charged in to shatter the monster’s standing leg. It screeched, stumbling in pain. A line of blood jetted across Vulkan’s plastron as he caved in a portion of the pteradon’s snout. It reeled before Ferrus sheared through one of its wings, leaving the membranous tissue ragged. Between them, the savage primarchs were tearing the monster apart. A bleat of panic escaped its throat, gurgling with the blood in its nasal cavity and mouth. The pteradon suddenly realised who was predator and who was prey.

It tried to flee but the primarchs were relentless, battering its wings with continuous blows and pounding its body like it was a carcass for tenderising. A flash from above presaged a jolt of lightning that struck Ferrus in the chest, winding him. He staggered and the monster was allowed to rise. Even though it was wounded, the hard beats of its wings were achieving loft. Another psychic bolt jagged down at Vulkan, but he evaded it and seized the pteradon’s flank.

“There’s no escape,” he muttered, gripping the edges of the monster’s scales and using them like handholds as the ground steadily fell away and he was borne upwards.

“VULKAN!”

Ferrus’ shout was devoured by the wind rushing into Vulkan’s ears. It whipped around him, whistling and screeching with the speed of the monster’s ascent. Battered by the rigours of the elements, Vulkan gritted his teeth and clung on. Amidst the tempest engulfing him, he heard the tolling of metal on metal. The anvil beckoned.

Crushed against the beast’s coarse flank, the world around him devolving into a shrieking blur, he knew he had to rise. When he pulled his hand free, the fingers of his gauntlet were rimed with gore from where he’d been digging in. Grabbing another armoured scale, Vulkan climbed. It was slow. Every moment held the threat of him losing his grip and being cast into arboreal oblivion below. Split branches fell like rain as they reached the forest canopy and surged through it. They scraped like claws across his face and for a few seconds he was blinded, his vision filled by parting foliage. Vulkan held on.

The striking of the anvil tolled in his ears.

After they’d breached the jungle roof, he was able to claw a little further up the pteradon’s body and reached the bony nub of its foreleg. He fought the pressing sense of disorientation as all visual and auditory markers disappeared in the maddened ascent. Heavy wing beats throbbed painfully in his ears as direction lost all meaning. There was only the need to hang on and the will to climb. The beast flew higher.

The sun still burned the sky, but it was wreathed in cloud as the monster rose, ever further into the heavens. It couldn’t shake him. It barely had the strength to climb, so Vulkan only needed to bear the raging wind that pulled at his body and tugged at his fingers.

He dug in and ate up the slow metres to his prey. His mind retreated back to the lava chasm all those many long years ago.

It was another life.

Reaching the muscular join between the monster’s wings, he found his enemy.

“Witch!” he called, bellowing to be heard.

She turned, looking over her shoulder. Her eyes flickered with psychic fire, and a bolt arrowed past Vulkan’s face.

“You’ll need to do better than that,” he shouted.

She angled her staff at the primarch, releasing a lightning storm that scorched his armour and burned a scar down his cheek. Vulkan grimaced, but advanced undaunted. Each punishing handhold brought him closer than the last. Underneath his body, he could sense the monster tiring, hear its laboured breathing and feel its shuddering muscles as they reached the end of their endurance.

Unable to climb any further, the pteradon pulled up and levelled out, enabling the eldar seer to leave her saddle and stand upon its vast, muscular back. She confronted the primarch, feeding power into the blade of her sword.

Vulkan was on his feet. He drew his hammer, slowly and purposefully to allow the full import of what fighting one of the Emperor’s sons meant to settle on the seer.

“Surrender now and it will be swift,” he promised.

She ran at him instead.

Vulkan charged.

The primarch’s footing was uneven across the monster’s back but he reached the seer without stumbling. The rune-blade whickered like a viper’s tongue, raking Thunderhead’s thick haft. She struck again, scoring a pectoral armour plate. Vulkan swung but she sprang away from the death blow, impossibly agile, and landed perfectly on the pteradon’s back. She lunged, aiming for Vulkan’s heart. The thrust penetrated the primarch’s guard but was turned aside by his armour. A crack presaged the breaking of her sword. The seer gasped at the psychic backlash, recoiling instinctively as the energy tore at her, clutching at a blackened arm.

Seizing her throat in his gauntleted fist, Vulkan bore the eldar witch down.

“This world belongs to the Imperium.”

She’d lost her staff, dropped over the edge of the monster, and her sword was a smoking hilt she’d also cast aside. All that remained was her defiance.

She spat over Vulkan’s armour, and there was blood mixed in with the phlegm.

“Barbarian!” The Imperial dialect sounded crude on her lyrical tongue. “You don’t know what you’ve done…” Her pale lips were flecked crimson and the vigour in her eyes was fading. “If you destroy it… you will doom this world more than you have already.”

Vulkan loosened his grip and was rewarded with treachery. A burst of psychic fire flared between them and he withdrew, letting the seer go. A second blast threw him off his feet and he was scrambling to hold on.

Panicking, the seer mounted the saddle and drove the pteradon into a suicidal dive. With a vertiginous lurch, Vulkan was falling and he reached out desperately for something to hold on to as he pitched over the pteradon’s side.

She was chanting. Her lilting refrain unleashed spear-thick barbs from the forest below. Vulkan narrowed his eyes and he dug his fingers between the plated scales. Stomach flat against the pteradon’s gelid hide, he weathered the debris storm that was suddenly bombarding him.

Descent was swift. The strain of it pressed against the primarch’s body like a gauntleted fist slowly clenching. The beast was almost done, plunging like a stone. It penetrated the broken leaf canopy as if breaching the atmosphere of a foreign world, but there was no fire, no aura of re-entry heat, just wind and the ground rushing to meet them. As the monster plummeted, Vulkan’s grip loosened. Inertia was dragging the scales he was clinging to, threatening to rip apart the sinews holding them together and tear them off.