The King in Yellow
From Tatters of the King

An ill defined creature, perhaps also known as 'The Living God'.
The King in Yellow dwells in Carcosa and is feared by the inhabitants of Yhtill and Alar.
In the Play
In the play Carcosa, or The Queen and the Stranger, The Stranger, also known as 'The Phantom of Truth' attempted to resist the King by the use of the 'Pallid Mask'. It seems this was unsuccessful.