Well if demons are real then the devil is real and if there is a devil there has to be a God to keep things equal like Ying and Yang can't have one without the other to keep things balanced between good and evil or whatever. What I saw was on the side of the road it was so black headlights on the truck could not penetrate it to show any shape and it had red fiery eyes that stared at me as I drove by and closest I was was about 10 feet when I was right next to it and all I saw were the red eyes starring and they were self illuminated and being that close still could not make out a shape besides black that was so black it was darker than the night at midnight which is the time frame I saw it.
First, I am in no way discounting your experience, but do have a slight philosophical disagreement on the correlation between existence of "demons" = existence of G-d. As demons have been a part of human myth, folklore and religious belief across continents and time, it would not necessarily correlate that their existence correlates to the existence of G-d, in that this 'version' for lack of a better word, of demons is largely based on a Judeo-Christian - more Christian even than Judeo - notion of both entities. Beings with the appearance you describe while existing, may be the manifestation of other planes of existence, other spiritual beings or other energy forms - whose existence could be as much of G-d's creation as you or I, or be a natural creature not yet understood. I also do not discount people's feelings of dread or fear around certain paranormal entities, but I am reasonably sure that that dread comes from a lack of understanding, not necessarily because of inherent, Satanic-specific evil-ness. Very interesting encounter kskattebo.