I noticed that you have sent your agents to the outskirts of the Imperium to spread dissent. Indeed, many of them appear to have been hugely successful. Numerous worlds have converted to Horus' banner without the need for any valuable space marines to be sent to those world. I congratulate you for this insidious endeavour.
But then in the Istvaan system, your marines interjected to prevent some of Angron's World Eaters from joining in the hunt for Corax. Through this action, you effectively kept Corax and a small contingent of his Raven Guard legion alive and well.
My dear Alpharius, why let Corax go when you sell entire worlds to Horus? Surely Corax's quicker demise will bring about the defeat of chaos all the faster by allowing Horus to win?
Your loyal servant,