The haiku doesn't describe Hastur. It tracks him.
Faceless king descends,
Tattered yellow swirls the void,
Madness in his wake.
Three lines, three motions: arrival, disturbance, aftermath. Notice what's missing. No adjective for the face, because there isn't one. No description of what the madness looks like, only that it trails him like weather. The haiku form forces this restraint, and the restraint is what makes it unsettling. You're told the least amount possible, and your imagination fills in the rest badly.
The art follows the same rule. Hastur isn't rendered so much as implied: robes that seem to be dissolving into the space around them, a shape more than a figure. He's not fighting the chaos in the image. He's generating it. That was the instinct behind this piece: horror that doesn't show you the monster, it shows you what the monster does to the air around it.
Hastur has been passed hand to hand for over a century, from Ambrose Bierce to Robert Chambers to Lovecraft, each writer adding dread without ever fully describing him. This piece sits in that tradition. The less you see, the more the piece asks you to imagine, and the worse that imagining tends to get.
