Hastur is part of the Old Ones, a loosely connected group of alien entities which in the pre-human history of Earth formed a ruling class, acting as physicial gods for pre-human lifeforms.
The creature is known by many names including the Dead God and the Horned King. It is deeply linked with the magic of dreams and bears some connection to the King in Yellow. Speaking the name "Hastur" aloud is rumoured to draw down the god's attention upon the speaker.
Origins
Like most of the deities present in the Strange Aeon, Hastur comes from Elsewhere, possibly from physical space such as a distant star or possibly from a seperate dimension. The truth is unknown.
Pre-History
Hastur's exact position during the reign of the Old Ones is unknown. Cult stories claim that the being ruled along with Cthulhu and other Old Ones but are unclear in regards of how.
Present Day
Only a few years ago, The Children of Chaos used powerful ritual to bring down an avatar of Hastur on the Cursed Plateau of Leng, the Dead King. From its strong hold the physical incarnation of the deity rules the Rapine Storm and The Disciples of Death's Shadow through their dreams.