The King in Yellow Arc

BBEGs

The King in Yellow (Hastur) Nyarlathotep The Palid Mask (Servant of Hastur) What do they want? The King in Yellow desires power, enslavement of mortal races. Thralldom of all life on earth.
Nyarlathoteps desires are unknowable. He enjoys messing with with mortals for some reason. (Trickster God?) Because of this, he has forme da nebulous alliance with Hastur

Book of Vile Darkness

Originally written by Vecna, This grimoire contains every evil in the cosmos. It is a gruesome catalog of all mortal wrongs. It was destroyed, for a time, by a mad or possibly benevolent mage who kept it in his possession for 100 years, Enduring the evil that wrought his mind and body. After this period had passed, he was able to perform a ritual in the book which destroyed he and the book for 3300 years. But it has inevitably reformed itself on the material plane. It is believed to be in the country of Sunwilde. Hastur has taken over Sunwilde after the death of the old king Umr' a'Tawil (was he killed by Hastur?) The book of vile Darkness contains rites to enthrall people on a large scale. Curses and incantations to dominate the minds of men.

Other Obstacles

The order of the Perpetual Shroud - They secretly desire the success of the Great Old Ones. They are exhorbitantly wealthy and will spare no expense to thwart the party and get the book in the hands of Hastur. Their ally Sebastian is a former member. But he believes these creatures should not be helped as it will destroy humanity.
The pyramid in Olorun contains a lost map to the actual book (star map?) it is guarded by a Mummy Lord (Kheifu) the actual book is in a sunken temple in the Eternal Desert. Guarded by....
Key items

• the King in Yellow (Play)
• The book of vile darkness
• Eye of Yog Sothoth (talisman)
• Talisman of Pure good? (How does this appear?)
• Necronomicon of Hastur. (brougth here with The King in Yellow) 

Plot points/Scenes

Party finds the eye of Yog Sothoth -> Sebastian reveals all -> They travel to Sunwilde and face challenges along the way -> Learn of the King Umr' a'Tawil's death and ascendency of someone known as The King In Yellow (Nyarlathotep befriends the party?) -> Learn of the Book of Vile Darkness and the King in Yellow is beint on Acquiring this tome. -> Learn that the last person to ever hold or see this tome in person is entombed in olorun. Perhaps a clue can be found in his grave. ->Party finds a starmap that reveals the position of the book -> Appears to be in the Eternal desert somewhere, in a sunken pyramid -> either the party or the Perpetual Shroud Acquires the book -> Either Nyarlathotep betrays the party or the King in Yellow summons all his strength to get the book back from the party. Many fights ensue Hastur and Nyalathotep are powerful enemies. -> how to destroy the Book of vile Darkness?

Events in the world

• The Yellow star of Carcosa is seen in the night sky starting at a specific date. It grows brighter and brighter as the story progresses. Soon it is like a second sun in the sky.
• The King in Yellow - A dreadful play opens in a country (Volgot?). Audience members say the play changed their life and outlook. Friends of these audience members report them to come back "altered" somehow, after they witness the play performed.