The reference to the Iron Warriors’ short-lived Heresy-era realm was lost on Ventris, but he kept his silence while the primarch continued to speak.

Guilliman looked to the sky. Past the veils of dust, the atmosphere was so thin that the brightest stars shone in the day and the lights of ships in orbit were clearly visible. ‘And yet I return to life and find the entire Imperium a prison for its people. By avoiding one problem, I created another. If I had left Ultramar intact, more worlds would have been havens from such pain and remained centres of reason. A bigger beacon burns brighter. I should have left it whole, as an example of what can be.’

The primarch turned to his son. ‘You are so many generations removed from the original founding. You remain true to the Imperium. The dedication of the Ultramarines is a testament to the spirit of Ultramar and the will of the Emperor. It would have been better had more worlds been in your keeping. You must understand why I did what I did. I watched half my brothers fall to Chaos, and became determined that no one should ever hold the power of a Legion again. I became obsessed with the potential misuse of a few hundred thousand Space Marines, and in doing so I forgot about the petty self-interest of lesser men. This is I, whose preoccupation was to hurry the Great Crusade to an end so that I could get on with the business of peace!’ He laughed at himself. ‘Perhaps I would have failed there. These rulers who deny my seal and my right to revoke our treaties, they are not evil – they are perhaps not even stupid. They are simply limited as all men are limited.’

Guilliman fell silent, then smiled sadly. ‘Does it shock you, my son, to learn a primarch can err?’

Ventris looked uncomfortable. ‘My heart says yes, but that primarchs can be mistaken is an obvious conclusion when the argument is reasoned through, my lord,’ said Ventris. ‘Your admission does nothing to lessen my respect for you. We of the Ultramarines remain human, despite our transformation. We make mistakes. As a son grows, he learns that his father is not infallible, whether he is glorious or humble.’

‘Sometimes I wonder if I am human at all,’ said Guilliman thoughtfully. ‘In any meaningful sense.’

‘If you were not, you would not care for the fate of other men.’

‘Many of my brothers did not. Maybe it is an affectation?’

‘Humanity is not measured on form alone, but by deeds, my lord,’ said Ventris. ‘A mortal man may be inhuman towards other men, yet I have seen xenos behave with honour and fairness when we offer them nothing but hate.’

Guilliman appraised the fourth captain carefully. ‘You impress me, Captain Ventris. I have heard much about your deeds. I did not expect you to be so thoughtful.’