Grammatic relationships inside a sentence - parsing

Question

once again I need again your help: I have this sentence and also its translation (same auther/text as here) :

まだどこにも兆{きざ}していない死苦{しく}が、感覚{かんかく}を灼{や}けた鉄{てつ}のように真赤{まっか}に鍛{きた}えてくれるのを感{かん}じた。

I think I understand the first part well enough (まだどこにも兆{きざ}していない死苦{しく}が)

but I have problems parsing the second part because I am unsure which parts belong together and why it is 死苦 that heats the feelings. Furthermore, I have trouble understanding the role of くれるの.

Anyway, I believe at least that 感覚{かんかく}を灼{や}けた鉄{てつ}のように真赤{まっか}に鍛{きた}えて belongs together.

Thanks a lot for any help.

Answer 1

鍛える ("to train") is a transitive verb. Its subject is 死苦, and its object is 感覚. 灼けた鉄のように真っ赤に ("red-ly as heated iron") is an adverbial phrase that modifies 鍛える. This adverbial phrase is 結果構文, therefore "I felt the deadly pain sharpen my senses so that they became red like heated iron" is the literal translation. It probably sounds fairly peculiar, but I think the original Japanese sentence is equally peculiar.