Hammurabi Unferth

"'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.

TTS Canon
As the Shield-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. Hammurabi joins Kitten's Mars Delegation as they are teleported to Mars by Magnus to speak to the Fabricator General about the Proteus Protocol. During their musical debate with the Fabricator General, Hammurabi adds his own wit to Kitten's arguments, including how arguing against the Captain General amounts to disagreeing with the Emperor's word. He later joins the other custodians in heaping praise upon their victorious Captain-General; claiming that they have come to see him as a father-figure, rather than a war master.

Trivia

 * Hammurabi Unferth's names are likely both references. King Hammurabi of Babylon was an ancient king, lawmaker, and diplomat, while Unferð, also translated as Unferth or Hunferth, was a pugnacious character from the epic poem Beowulf.