comic source (website) Explanation from a WH40k nerd friend:
Gulliman (the ultramarine primarch) is oft is basically king of admin and logistics
he is the spreadsheet lord
well the others were turning people into a floor made of human agony or being goth vampires he was looking at his 500 planets and doing the bookkeeping on why wheat production was down by 2.54% on one of them
one of the things that happened when he came back was the inquisiton went into a civil war based on calanders
because he wanted a consistant and uniform way to tell the dates of when things happened
yes that happened
Amazing thanks highly efficient 🥰