C'tan World Engine novel feat

"In the centre of the debris cloud rose a burning ember, a mote of fire ascending from the darkness. It gathered matter and light into itself like a black hole pulling at the surface of Borsis. Hyalhi let the image of it burn into his brain, sinking in deep, because this would have to be remembered too.
The being that formed in the centre of the zone of destruction hovered above the tallest spire, and its body was composed of darkness. It had no fixed shape, its only definite feature the crescent of three eyes that burned in its heart. Tendrils of it, composed of torn and compacted metal, dragged it along above the spires. Hyalhi did not have to picture the geography of Borsis to know where it was headed.
What followed had to be remembered as well. Hyalhi turned his consciousness this time outside his body, riding the ripples growing in the warp from the impact of the being erupting from its prison. He could see Borsis unfolding beneath him, the endless steel canyons and metal spires rushing past. The Astral Knights had fought across much of the planet's surface but now he saw, from his high psychic vantage point, great palaces and monuments the Astral Knights had not seen. It was the work of endless millennia, the labour of countless scarabs and worker-constructs devoted to deifying their nobles.
The entity roared up ahead, shredding the spiretops as it passed and absorbing the fragments of matter that flew up into its swirling mass. Limbs formed and reformed as it hauled itself along, and pulses of raw, alien hatred battered against the surface of Hyalhi's mind. It was not a human emotion, for there was nothing human about this being, but it was unmistakably hatred.
The entity crossed into the Labyrinth Wastes. It passed over columns of warrior-constructs arriving to join the final stages of the battle, and those that could feel dismay felt it now as the great darkness bellowed and stormed overhead.
(...)
Silver and gold glittered as Overlord Heqiroth and his lychguard retinue arrived on the battlements. The darkness bore over them as the moon that passed closest to it was torn apart and absorbed into its body. Heqiroth took one look at the approaching entity and the silvery necrodermis swarmed over his body in a protective shroud.
An arm of compacted debris swept the lychguard off the wall. They tumbled down the side of the cathedral along with tonnes of shattered battlement. The darkness loomed closer and the necrodermis squirmed off Heqiroth's body as if of its own accord, drawn off in ductile streamers into the swirling blackness.
The entity wove the necrodermis around it into the form of the star-god the necrons had first beseeched, then worshipped, then destroyed. Even this single shard of it was terrifying to see taking shape – it was like a deity of destruction and calamity from some long-forgotten human religion, crowned with three burning eyes, its enormous form clad in liquid metal.
Hyalhi did not know the necron language in which Heqiroth spoke to Yggra'nya the Worldmaker, the C'tan imprisoned in the heart of Borsis to power it and guide it towards Mars. It was not a tongue that even needed sound, transmitted in pure information. But Hyalhi could guess it involved pleading, perhaps bargaining, Heqiroth offering lordship of Borsis, every necron under his command, everything he could possibly give in return for being permitted to continue existing.
And Hyalhi knew the reply, too. "You betrayed us", Yggra'nya would be saying. "You imprisoned us. You enslaved us to this mad plan to journey to Mars."
Heqiroth held up the tesseract in which he had imprisoned and then recaptured Turakhin, no doubt trying to persuade the C'tan that its enslavement had been Turakhin's doing. Yggra'nya snatched the tesseract and it dissolved in its hand, consumed by a purple-black fire, and with it the last glimmer of Turakhin's existence. But it was not enough.
"You, Turakhin, all that came before, you are all the same." Hyalhi could almost hear the star-god's words and their meaning could not be in doubt. "The whole necron race is our enemy. Now I am free, and you will all be punished."
It gave Hyalhi some measure of satisfaction to see Overlord Heqiroth lifted off the battlements and dissected, piece by piece, by the will of Yggra'nya. Each section peeled and lifted away, gradually reducing the overlord to a spindly metal skeleton that squirmed in pain, if necrons could feel it. That, too, was dissolved away until only a glimmering speck of consciousness sat in Yggra'nya's palm. Then the C'tan closed its fist and Heqiroth, too, was annihilated.
Yggra'nya raised its arms as if making a sacred pronouncement. The substance of the Cathedral of the Seven Moons came apart and reformed above it, an endless torrent of shattered metal forming great rings that orbited the star-god. Then they became gigantic blades that Yggra'nya stabbed into the surface of Borsis, driving them deep down through the crust of the world it had once built in an earlier age of the galaxy.
Yggra'nya dived into the fissure it had opened up. Hyalhi could feel it ripping through the planet, dissolving everything in front of it like a blowtorch through flesh. It tore through the vast power sources that drove Borsis, through the chambers where warrior-constructs were assembled and repaired, through the necropoli of long-forgotten dynasties and the vaults full of war machines and spacecraft. It shrieked through the core of the planet and looped around again, riddling Borsis with molten destruction in its rage.
The sky changed from a grey mantle of cloud to a patchwork of light and dark as the cover was blown away. Hyalhi knew what that meant. With the destruction of the generators and reactors at Borsis's core, the shielding around the planet was failing. Whereas before Borsis had been impervious to the torpedoes and lance batteries of the Varv Deliverance Fleet, now its surface was laid bare and open. Hyalhi realised he had been holding his breath, for now he breathed it out in relief.
(...)
Yggra'nya hovered there, its three eyes turned down towards Hyalhi. There was no doubt the star-god could see Hyalhi. He was the last Astral Knight left on Borsis. Perhaps Yggra'nya wanted to pay its respects, though Hyalhi doubted it.
Hyalhi looked up into those burning eyes. Men would have gone mad to see it, but Hyalhi was not afraid.
'We will find you!' yelled Hyalhi at the star-god. If it heard him, it gave no reply. It simply shot up into space, the silver streak of its body vanishing into the void.