“Our insignificance may save us”
The story is well written. Sentence by sentence you say see that the author is on the top of his game. Read the Wendigo before this, but it didn’t leave the lasting (at least I hope with my subpar memory) impression.
Most of us can’t help by being scared of the unknown. The Swede and the narrator flash out two probable reactions to both in the middle of and completely surrounded by something that is so horrifying yet something that can’t be comprehended. Our brains need to identify something. Blackwood plays with that idea and finds a terror that is totally outside of our perception. That is what makes the work so appealing. I think that is why Lovecraft was also so drawn by it. During the era where Blackwood hit his peak, most ghost or horror stories were the now bland ghost or monster thing that had in themselves roots in our lives. He shifted the perspective masterfully.
But back to the Swede and Narrator the two probable reactions to ethereal and eternal unknown. The Swede (unlike the stereotypes) is far more volatile, far more prone to jumping to an irrational conclusion. The narrator is more of an adherent to logical, or reason based thinking. But as we see in the story, reason can only bring you so far. There are times and events when you just have to take the leap towards the unexplainable and accept it as something beyond human limits.