I don't "assert" things, even if I believe them. I'm an agnostic theist. In any case, I don't believe a "supernatural realm beyond our comprehension" is necessary for Gods; they can be very, very immanent. For the record, I do believe in an intangible realm, but not that it's inherently "beyond our comprehension".
It's... similar, though perhaps more fatalistic. Wyrd is not so much "fate" as it is "destiny".
And in pre-Christian European conceptions, nothing "made" it. It just... is. The story given in Edda Lore is that there was just a Yawning Gap, and then Fire-Land and Ice-Land (not the country) just... appeared. Then they just crept closer to each other, and as their inter-influence increased, Ymir was just born. Then a cow named Audhumbla was born from the same process, and she licked the ice and uncovered Buri, father or Bor, father of Odin, Vili, and Ve. No "Creator" did this; it just happened.
In my personal conception, the Sole Eternal Being is Death, who is the Mother of Life. The Firstborn of Death is the Weaver, whom I conceive of as a spider, and Her Web, ever being spun, is basically Wyrd. But a spider is significantly smaller than Her web, and the threads can be altered by a delicate external force whether She wills it or no. (...hey, I could use that to tell a Promethean story).
Here's a practical example. It is the Wyrd of humanity that we cannot fly. It wasn't through Seiðr, but that thread was ultimately altered; such that our bodies still cannot fly, but we have built tools that enable us to do so.
I would argue that god does not exist in a physical or material realm and that is why I would say it requires a supernatural realm for a god to exist.("assert" was perhaps a strong word as I'm obviously speaking from a contrary point of view).
I tend to think of existence less as something which is determined or fated. But I know what you mean by saying it just "is". I tend to be a bit suspcious of the concept of a "Big Bang" as the origin of the universe (from a position of ignorance), as it leaves the cause unexplained. So again, I don't believe there is a creator and that the world just "is" and always has been.
Death is pretty central to understanding life and once we become aware of "him", he is our constant companion. (I'm being honest, in that I think of death as a person, waiting at some metaphorical door to take us away, as it is hard to think of it in a realistic way. perhaps death is a shadow of my future self yet to be realized). I suppose the difference between fatalism and determinism can best be seen in regards to death; fatalism says the time, place and way we die, whereas determinism would argue only that death is a necessary result of the exhaustion of our biological existence- it does not suppose that it is a fixed point in time only an ultimate- destination. Our journey there is still the product of our freedom.
I like the story of the weaver-spider. Spider webs are very beautiful in morning dew. As the spider is symbolic of death, are we the flies to be caught in the web of fate?
I see many of your points, thank you for your candor!
So, why is religion necessary if it's not really driving the world to become a better place?
Part of my point is that atheists often get a bad rap by many religious sectors and it's funny to me considering the state of the world and the fact that atheists are well in the minority.
Religion is necessary to conceive of our place in the world. The evolution to a point in our understanding where we become conscious of our own power, when we become as close to gods as it ever possible and therefore won't need religion, is hinted at in religion and so are its dangers. Yet in religion, it remains illusive since it is not man that makes the world a better place, but the divine which we neither fully comprehend or control.