TLDR: Human spirit and sacrifice clash against the greed and self serving nature of humanity. Great and progressive story building, character building, with few to no unanswered questions at the conclusion. Most Chinese novels i've read up till now have ridiculous endings that read like a poor copy of a dragonballz episode (coiling dragon was good, but lets be real the ending sucked.)
This story completely blew my mind. Moral men and Pedantic preachers stand opposite a thin line, more so in a story pieced together chapter chapter by chapter in such a web novel format. And so, the character building in this story becomes all the more surprising.
Spoiler from here on out.
A child at the beginning of the novel, the MC is naive, his pursuits and choices simple crude; a true country bumpkin. Perverted, small minded, but with his own bottom line. Many novels start like this and thats all fine and dandy, but what destroys the depth of those novels is one huge 'story event flag' which from then forth decides the characters choices, all personality traits and plot directions derive from this singular event and the main characters actions thus lack depth because of the singular nature in his environmental influences. CBI avoids this, which makes for a slow start, but like the tree in the castle of black iron, our MC grows LIKE A BELIEVABLE REAL PERSON. Every stage in his life has different influences, and in every stage we can see his choices and his level of vision change in response to these influences.
Cultivation in this novel is super unique, and the MC's 'cheat item' doesnt block or cover over his character. Most novels with a cheat like item make you feel that if someone else had the same item as the MC, they would be the exact same person. MC isnt a unique person. But in the case of castle of black iron, the space and his best tree buddy grow and change along with his choices, the castle acts as a support, a best friend, a resting place, and not an all conquering god weapon that makes resistance against the MC futile.
Instead conflict in this novel ends up varied, believable, dangerous, and all the more enticing for the reader. The MC has gains and losses, wins and defeats, and his growth occurs in this journey because of the challenges and conflicts present in this unique era he is in instead of the presence of a deus ex machina type item.
The one and only minor short board is the depth of female interactions. Note I say interactions instead of characters, because these females are each unique and have their own thoughts and do conflict decision wise with the MC even after together. Further, this shortboard is made up to some extent by his interactions with his family (brother mother father). Further, the lack of depth in exploration in the relationships with his female partners can be explained and feels reasonable to an extent because of the huge weight of the increasing burden on his shoulders, he wouldlove to spend more time with his family but the never ending war blocks him from being the father and husband he wants to be. Its reasonable, and therefore doesn't detract from the story so much as make a reasonable and natural cover for the inherent flaws in any novel with a harem.
Read it, please, because id hate for such a masterpiece novel to be buried by the glare of its mediocre early translations and its slow start.