"I thought we were going to discuss the Emperor's affinity with BBQ sauce today, but okay, sorry. My mistake."
Hammurabi Unferth is the Shield-Captain of the Emissaries Imperatus of the Adeptus Custodes.
As captain of the Emissaries Imperatus, also known as the Heralds of the Golden Throne, he and his men are trained to act as the Emperor's direct representatives when dealing with other Imperial commanders. Their chief tactic is passive-aggression, as Kitten puts it, "having mastered the subtle art of the guilt trip". Unferth in particular guilts Kitten and his subordinates at every opportunity. Kitten is unfazed by his antics, having heard it all before.