Nyarlathotep first appeared in the 1920's and is described as resembling an ancient Egyptian Pharaoh. In his first story, he is shown wandering the Earth in search of gathering followers through magical instruments. The followers lose their awareness of the world and there is an impression that the world has collapsed.
Nyarlathotep is a major character in the story " The Dream Quest Of Unknown Kadath" in which he manifests into the form of an Egyptian Pharaoh and confronts the character Randolph Carter. In the "Dreams In The Witch House" story in 1933, he appears to Walter Gilman and the witch Keziah Manson in the form of the 'Black Man', a black-skinned form of the Devil. He is also mentioned in the "Rats In The Walls" story in which he shown as a faceless god in Earth's centre. He also has an appearance in the "Haunter Of The Dark" story where he is shown in the form of a bat-winged monster in the steeple of a Church.
Whereas most Outer Gods are ambivalent to, or unaware of humanity's existance, Nyarlathotep is unique in that he delights in causing suffering to humans.
It has been suggested that Stephen King's Randall Flag is among the avatars of Nyarlathotep.
Nyarlathotep is an omnipotent demonic deity. Just his presence alone can cause insanity. He is the messenger of the old ones. Black Pharaoh is the abstract of chaos. He enjoys madness, and inflict on mortals with it. Nyarlathotep is the son of Azathoth. Nyarlathotep can't die, does not require food, water, and air. His shape-shifting is extraordinary,and the Black Pharaoh has other abilities like super strength, immortality, madness manipulation,mountain creation, illusion casting,reality and dimensional manipulation.
He can manifest to 1,000 forms.
Here are just a few:
1. Samael: The angel of death.
3. Black Pharaoh
4. Messenger of the Old Ones
5. Randall Flagg: The Stand & The Dark Tower comic series.
6. Mr. Skin.
7. The Faceless God.
8. Dark One