2 questions about one sentence
【"Oh! captive, bound, and double-ironed," cried the phantom, "not to know, that ages of incessant labour, by immortal creatures, for this earth must pass into eternity before the good of which it is susceptible is all developed. "】

1. what does "immortal creature" here mean?
2. in "the good of which", what does this "which" indicate? the earth's good? or the immortal creatures' good?

Question

2 questions about one sentence
【"Oh!  captive, bound, and double-ironed," cried the phantom, "not to know, that ages of incessant labour, by immortal creatures, for this earth must pass into eternity before the good of which it is susceptible is all developed. "】

1. what does "immortal creature" here mean?
2. in "the good of which", what does this "which" indicate? the earth's good? or the immortal creatures' good?

Answer

Well immortal is an adjective that describes a noun being a person or a living creature that cannot die. Creature is the actual noun. All in all, an immortal creature is a living thing that cannot die.