I don't see FW as materialist.
There are no gods in the religious sense... like... a magical person that KNOWS what's right and wrong always for everything and thus justifies any behaviour if enacted in its name.
But... there ARE spirits and magic and metaphysical entities. Matter can be a by-product of mind and spirit. No problem :)
What is true though, is that I strongly feel that morality is relative, and I worked really hard in the design to make it so Players and World can't misunderstand it.
Characters can believe in absolute good and evil, and the game never tells them they are wrong... but it TESTS this belief, it makes them question it. They they surely can answer "Yes, that's exactly what I believe" at every turn. But the question was posed and played through. Repeatedly explored to discover its limits.
This. It never occurred to me that this could be a relevant thing to mention in describing the kind of fantasy stories the game supports ^_^'
I'll have to ponder on this point. It's very interesting :D