Cawl broke off his automata and swung them around before they got too close to the creatures. One of them lunged out from the swarm, a serrated blade on the end of its limb slicing down at his lead machine Cawl saw it coming, and made the robot dodge aside with a burst from its manoeuvring thrusters. At that distance, it took half a second for his commands to reach the machines. That was far too much lag. The creature's weapon missed his device by mere inches, then he was past. He got a quick view of the magnitude of the swarm. Thousands floated from the deeps, their crystalline armour glinting in the endless lightning.

'I recommend an immediate withdrawal,' Cawl stated, data-pulsing a pict capture of the rising swarm to his mistress. 'See what ascends, domina.'

Aspertia spared a picosecond of consideration. During that brief time she appraised the tactical situation herself, and performed an analysis of the extractors' progress.

<Negative,> she canted, so everyone could hear her dismissal of Cawl's suggestion. <We have not reached resource parity for this mission. Departing now would result in a net loss to the Mechanicum. Remain. Fight.>

Cawl once again intruded himself into the robots, boosting them back towards the fight. The situation was worsening by the second. Thousands of the creatures were attacking, picking off the extractors' defenders, getting closer to the larger machines pillaging their domain. Cawl had his maniple concentrate fire on the largest of the creatures, a monster fifty metres across. His autocannon shots blew chunks out of its armour. Multiple missile impacts detonated across its upper side. It was still advancing on the scows as he turned his robots again, and flew them to a safe distance. The Mechanicum didn't even know why these things swarmed the extractors. They didn't seem capable of eating either flesh or metal. It could have been purely territorial, of course. It didn't matter. They had to die.

Cawl sifted through the mass of data exloaded by his charges. The extractors were at seventy-four per cent capacity. Every dead automaton meant that number had to be higher. Battle was a game of economics; cut and run now, and they would be in resource deficit, but staying to even it up might worsen their losses.

Cawl was about to swing around for another pass when his forward augur display lit up with dozens of new contacts.

<More xenos, coming up from below. They're targeting the rearmost extractors.> He pulsed emotionlessly, like a machine, as befitted a man of his calling. His heart, however, pounded with adrenaline.

Aspertia ordered more of the robots to break formation and head off this new threat. The shifting polyhedron shrank closer to the extractor rafts. There was now fifty metres between the overlapping fields of fire of the automata and the outermost parts of the rafts, no more than that.

'This is going to be close,' muttered Cawl.