‘I predict their response will be nothing short of furious, my lord regent. They hate Belisarius Cawl. Envy motivates them if they knew the extent to which his knowledge outreaches theirs, some would move to destroy him and his creations. I trust you will shelter me should the time come.’

Guilliman laughed. He did not laugh often now, and when he did it was sorrowful. ‘The Cawl Inferior, you betray your disguise. You wish for protection as a living being would.’

‘I require it. I do not desire or not desire it. My continued existence is necessary. If Cawl dies, the sum total of his knowledge exists within me. That is why I must live. If he dies, you will at least have me. Archmagos Belisarius Cawl can protect himself. I cannot.’

‘Archmagos Cawl is the last being I know who needs protection from anybody,’ agreed Guilliman. ‘And you are safe here in the bowels of the Macragge’s Honour. Now, the Primaris Space Marines. We have a century of data. How are they performing?’

‘Archmagos Belisarius Cawl repeats that all gene-lines continue to operate at peak efficiency. Tested gene-seed reveals a mutational deviancy of less than 0.001% per generation. All Adeptus Astartes Chapters once again have access to the full suite of additional organs, replacing those zygotes lost through improper treatment or evolutionary variance, with the addition of the three new implants. All Chapters who have adopted the Primaris paradigm have adapted to the new creation processes with minimal wastage of recruits or mistakes in implantation. As can be expected, those new Primaris-strain Chapters founded by you, my lord, have the lowest error rate. The new equipment functions well. Requests for resupply with the new type of battle-brother and their associated weaponry have increased, suggesting a ninety-four per cent acceptance rate among the Chapters.’

‘What of those gene-lines with more deeply ingrained flaws?’ asked Guilliman. ‘The Blood Angels and the Space Wolves?’ Cawl’s research, and his own reading, had uncovered dangerous faults that the sons of both gene-lines in question had done their best to hide.

‘My standard response remains unchanged. Archmagos Belisarius Cawl understands your reservations. The corrected flaws in the new gene-stocks show no signs of regression to previous unstable states, whether in successor Chapters composed entirely of the new Primaris Space Marine type, or in already established Chapters. Elimination entirely of the more idiosyncratic traits of some gene-lines is, however, not to be recommended. They form part of the Emperor’s original vision, and are, in any case, crucial to their proper function. I will restate Archmagos Belisarius Cawl’s position on this matter. The improved gene-seed of Ninth and Sixth Legion stock is operating within acceptable parameters.