Steven King's "IT" was a pretty cool book too, IT was a bad motherfucker as well.
In "IT"...He apparently originated in a void containing and surrounding the universe, a place referred to in the novel as the "Macroverse".
"IT's" natural enemy is "The Turtle", another ancient Macroverse dweller who, eons ago, created our universe and possibly others. The Turtle shows up again in King's series The Dark Tower.
The book suggests that IT, along with the Turtle, are themselves creations of a separate, omnipotent creator referred to as "the Other". The Turtle and "IT" are eternal enemies, though "IT" tells the main character Bill that the Turtle died a few years ago when he "puked in his shell and choked to death on a galaxy or two". "IT" arrived in our world in a massive, cataclysmic event similar to an asteroid impact, in the place that would, in time, become Derry, Maine.
But "IT" is not nearly quite the evil son of a bitch as god is depicted in the bible. If you are looking for a good horror story filled with death, carnage, and unremorseful if not absolutely inhuman supernatural beings that want nothing better than to inflict pain and wanton destruction on humans, then the bible is certainly a good choice.