Clark Ashton was a librarian, but also secretly, he is the leader of the Cult of Cathulhu.
Clark Ashton is an official of the New York City Public Library. But that was a cover for his secret nature; years ago, due to his interest in the occult, led the Cult of Cathulhu, who worships the Old One known as Cathulhu.
During a rare celestial alignment, Ashton was placed in char of an exhibit of the Necronomicon, a book of spells with the power to summon forth Cathulhu. He finished establishing the exhibit on before the public display and left the library with Ted Klein, a teacher of Miskatonic University, after 6 o'clock that Saturday night.
A Spawn of Cathulhu emerged and stole the tome.
The following day, Ashton and the Cult gathered at Wagner's Occult Shop with the Necronomicon, revealing they were the ones who summoned a Spawn of Cathulhu to retrieve the accursed spell book under the guise of robbery. Their secret meeting was interrupted by the Ghostbusters and Alice Derleth.
Yet, Ashton managed to escape with the book as both him and his cult members managed to summon their idol from the other side. However, Cathulhu was defeated by the Ghostbusters and the Cult was arrested by the police. Ashton was unmasked by Winston Zeddemore. As the police hauled him way, Ashton yells out that this was not the end of Cathulhu and he would return.
- His full name is a reference to important Cthulhu Mythos writer Clark Ashton Smith.
- Clark's tirade, as he is being hauled away by the police, is a reference to famous storyteller H.P. Lovecraft's classic novel The Call of Cthulhu.