‘I was there,’ he would say afterwards, until afterwards became a time quite devoid of laughter. ‘I was there, the day Horus slew the Emperor.’ It was a delicious conceit, and his comrades would chuckle at the sheer treason of it.

The story was a good one. Torgaddon would usually be the one to cajole him into telling it, for Torgaddon was the joker, a man of mighty laughter and idiot tricks. And Loken would tell it again, a tale rehearsed through so many retellings, it almost told itself. Loken was always careful to make sure his audience properly understood the irony in his story. It was likely that he felt some shame about his complicity in the matter itself, for it was a case of blood spilled from misunderstanding. There was a great tragedy implicit in the tale of the Emperor’s murder, a tragedy that Loken always wanted his listeners to appreciate. But the death of Sejanus was usually all that fixed their attentions.

That, and the punchline.

It had been, as far as the warp-dilated horologs could attest, the two hundred and third year of the Great Crusade. Loken always set his story in its proper time and place. The commander had been Warmaster for about a year, since the triumphant conclusion of the Ullanor campaign, and he was anxious to prove his new-found status, particularly in the eyes of his brothers.

Warmaster. Such a title. The fit was still new and unnatural, not yet worn in...