Over 1,000,000 years ago, eons before the present day, the dark gods known as the Old Ones traveled from their home dimensions to Earth, ruling over it and feasting on mankind's ancestors. Eventually at some point in time sorcerers from Earth used powerful magic to contain or banish the Old Ones. One of these Old Ones was the evil Ghaszaszh Nyirh, who relished in mankind's debasement.
Strange Tales II
After Doctor Strange destroyed most all his artifacts to prevent his friends from falling victim to Urthona, the magicks locking out the Old Ones from the 616 reality were broken and they were free to terrorize Earth once more. Ghaszaszh Nyirh returned to Earth and chose to rule over an area of Africa that was plagued with great drought and famine. The local populace worshiped Ghaszaszh Nyirh, recognizing it as a deity of immense power, and prayed for it to relieve their hunger. Ghaszaszh Nyirh accepted the prayers of the populace, but as an evil god, Ghaszaszh Nyirh did not give his worshipers sustenance without a price. The food from Ghaszaszh Nyirh that was eaten changed their bodies to give them a grotesque physical appearance that defied logic.
The master of black magic and the Ancient One's peer, Kaluu, takes Doctor Strange to Ghaszaszh Nyirh's temple in southern Africa so as to tutor Strange in the ways of black magic and rid the Earth of the evil deity. Kaluu convinces Strange to transfer his very essence into the body of a 5 year old child whose mother sold her soul to Nyirh for a rice cake, and when the mother reaches its dwelling Strange uses his magic to create an explosion that destroys most of Nyirh's temple and kills many of Nyirh's human worshipers. This only humors Ghaszaszh Nyirh, who dares Strange and Kaluu to face him inside. Kaluu uses his vast knowledge to navigate them through the winding temple until they find Nyirh, who attacks them. Ghaszaszh Nyirh uses his trickery to change into the forms of both Strange and Kaluu so as to drive a psychological wedge between them, but it does not do so. He then reads Strange's mind and morphs into Clea, Strange's lover, but is trapped in that form by a spell. Ghaszaszh Nyir uses his power to create illusions of multiple chaotic entities, including Nightmare and Erlik Khan, but Strange and Kaluu continue their assault.
In a change of tactics, Ghaszaszh Nyirh goes after Kaluu and seemingly rips his heart from his chest. In spite of Kaluu's orders, Strange leaves the protective shield that Kaluu had placed on him, which leaves Strange vulnerable to attack. Ghaszaszh Nyirh exploits this and shoots a ray of chaos energy from his eye that dissolves Strange's left eyeball. Neither of the practitioners of black magic are able to stand up to Ghaszaszh Nyirh any longer, and so Strange flees the temple and detonates a black magic spell from the outside that completely destroys it. Kaluu, having used an illusion to guide Strange in Nyirh's temple, appears next to Strange outside and tells him that a consequence for his hesitation to use black magic was paying the price of his eye. But as the temple was Ghaszaszh Nyirh's gateway into Earth, its destruction effectively banished Nyirh out of the dimension.
In Invaders Now #4 (2010), Ghaszaszh Nyirh is invoked for power along with Shuma-Gorath in an incantation meant to bring Shuma-Gorath to Earth.
Power and Abilities
Ghaszaszh Nyirh is an Old One with great power. He is well-versed in energy projection, illusion casting, shape-shifting, telekinesis and telepathy, along with other forms of black magic. He is also able to create food out of nothing (in the story arc he offered worshipers sweet rice cakes), which turns its consumers into hideous versions of their former selves.
Ghaszaszh Nyirh's energy blast of dark magic that destroyed Strange's left eyeball was contained within Strange's body by Kaluu. This provides Strange another boost in magic power after he is no longer able to use White Magic. Dormammu is later able to reconstitute himself and enter Earth before taking over Strange's body, thanks to the remnants of Ghaszaszh Nyirh's dark power left behind Strange's eye.