Just as a watch could not exist without a watchmaker, a god cannot exist without a godmaker.
A god is supreme in that it is intelligently designed to be supreme. If there were a more perfect design for a god, then it would be natural for us to replace the lesser design with the improved one, just as watch designs have improved over the past few centuries. If there were a better, more perfect god design we would have ourselves a new god-template and soon put it to use. This is something we see manifesting itself in modern culture, with the many offshoots of any particular religion, each claiming to be more correct than the others, each trying to win converts from the others, each competing in the marketplace of ideas.
And what is a god-template? Clearly, the christian god-template is the bible, a book which describes, albeit abstractly, the many attributes of their god. The fact that it is abstract allows it to be interpretted in many ways, and gives us many flavors of the same kind of god, just as we have many different types of watches.
Now the question remains, who made the godmaker? Which is almost the same as saying who make the god-template? And that is one for another day.