There is no evidence for the existence of God.

[MineralMan]

46. Abour your "parable"

Why would anyone in that room suspect there were other rooms? What would be the thing that initiated the idea of their existence?

Unlike your blank room, the universe we inhabit has many windows. We have still not explored that universe fully. However, our long exploration of it has led to the hypothesis that there may well be other universes. That possibility is being looked at, at least mathematically. However, we still have unanswered questions about the one we inhabit that limit our ability to understand the multiverse, if it actually exists.

In the end, however, we are almost certainly restricted to the universe we inhabit. We may someday understand the multiverse concept, if it can be described, but we are unlikely to be able to actually observe anything beyond our own. It doesn't matter, though. The existence or non-existence of other universes does not have any impact on us. We're locked in our tiny little corner of the one we inhabit.

As for deities, there have been many of them invented by humans. They come and go. We don't even agree on the definitions for them. Like the multiverse hypothesis, it doesn't matter, though. Any deities that possibly exist seem to have no actual effect on our reality.