Sir Doom
Cooler than most of you
The concept 'God' is obviously a real thing otherwise you wouldn't have put it in your thread title. As it is, every concept 'God' is of equal value in terms of existence, and in fact occupies the same 'space' as similar concepts such as 'democracy', 'solipsism', 'esprit de corps', 'Teenage Mutant Ninja Turtles' or 'scrumptious'. Therefore, by invoking the word at all (as you have done) it proves beyond a shadow of a doubt that you yourself (deny as you might) hold a concept 'God' that you think is 'unreal'. Unfortunately, the only requirements for basic existence is: impact upon reality. If a thing affects reality, it is real. If it doesn't... well we never get that far, do we? Things that don't exist are non-perceptible. Everything else exists (at least as a concept), including 'God'. Evidenced by the fact that you, the OP, are in fact using the concept to affect reality in a way consistent with other similar concepts. I need no further proof of the existence of a concept such as God.