Centuries ago, when a great war was waged between Law and Chaos, the Sorcerer Ur-Nannu, renowned for his power, went with his armies to fight the King in Yellow. After many victorious battles, Ur-Nannu's forces were finally overrun in the Skaldian Pass. Ur-Nannu was taken to the King in Yellow's fortress, were he was tortured for many years for the devastation he had unleashed upon Chaos.
Ur-Nannu eventually escaped, and swore that, in revenge for his torture, he would make a mockery of the King.
And so it was that he wrote the play, The King in Yellow, which drove all who read the second act to insanity and despair, and placed them under the power of the King in Yellow. It is considered the greatest of the King's tools.
Yet the King despises it, for it mocks him. It is a work of art, admittedly, despite it's evil, and it is a work of culture and civilisation. For this, the King in Yellow hates it.
For this, though few realise, Ur-Nannu has his revenge. Through this, he has made a mockery of the King.