|Images of Pallid Mask|
Source: Black Stars Beckon, pg(s). 64
The Pallid Mask is a six-foot-tall slender humanoid figure garbed in a voluminous yellow robe emblazoned with the Yellow Sign, which can be concealed or revealed. His face is a genderless, featureless white mask with openings where the eyes, nose, and mouth should be. The mask is directly connected to soft tissue underneath.
During a tense political stalemate between the cities of Yhtill and Alar, the Pallid Mask sought an audience with Cassilda, queen of Yhtill, who needed to name an heir but could not choose her daughter Camilla, for fear of a prophecy that the Yellow Sign would be found by a successor to Cassilda's dynasty. He introduced himself as a creation of Hastur's enemies and claimed that his mask rendered him invisible to the King in Yellow, using his robe as evidence. He offered Cassilda a method to name Camilla her successor without drawing Hastur's attention, explaining that 'It is the shadow cast by the truth'.
This was little more than a ruse to lure the nobility of Yhtill to attend a masquerade held to commemorate the event. Everyone looked upon the Yellow Sign and thought themselves immune to it. When the hour struck, the attendants removed their own masks, and the Pallid Mask's true identity was revealed as Hastur drove all residents insane, and Carcosa consumed Yhtill.
Millennia later, even though there are more ways for Carcosa to feed upon other cities like Xhamen-Dor and the Star Stelae, the Pallid Mask still visits cities filled with decadence and nihilism to decide whether they should join Carcosa.