Question, can you compare this to ATG when 1. The girl who was going to break up her marriage agreement with him, is reluctant to do so because she doesn't want to make him look bad or hurt his feelings while he's in a bad situation, takes him outside of the city to do so because she wants to help him save as much face as possible, doesn't mind him pursuing her afterwards and even has a good attitude about it afterwards? This is not BTTH and it's not ATG. This is original and interesting.
And the fiance DOES care about the MC and does a LOT for him. The fiance isn't shallow. She didn't like the idea of pre-arranged marriage. That ISN'T shallow.
Also in TTNH's fashion, MC does indeed seem to probably come from some insanely OP background he never knew about before which makes this all the more interesting. Because this really opens up and broadens the mystery of just who the f*ck stole his spirit root, blood, and bone and why.
In my eyes, there are generally two kinds of strongest works. The first kind stays entirely true to reality; the author does so because he is talented enough to do so and doesn't have to create anything fantastical in order to tell a good story. The second kind is anything but true to the reality of everyday life; the author is able to create compelling and innovative original characters, ideas, and situations, and juggle them in a sophisticated way that allows him or her to convey something that often can't be conveyed as masterfully by talking about the world as it is because it is easier to understand the world by looking at what it would be like if some aspects of it changed.
Index is in its own category. It describes reality by both being more realistic and more crazy as a gigantic clash of ideals than anything else. Its strength lies in its originality. It fully engages ideas and situations that other authors would be afraid of tackling either because they're so controversial or simply so hard to faithfully represent. But Kamachi Kazuma is a true super-genius.
In the sprawling cast of 100's of characters are many of my favorite fictional characters. There is no such thing as an unextraordinarily well-written character in index. It has the best worldbuilding, the best motifs/themes, the best plot twists, characters, etc. and it's deep, not a waste of time. The author anticipates what the fanbase wants and always throws curveballs. He is extremely prolific and is a true genius, and he genuinely cares more than I've ever seen another author care. He bucks all tradition and develops his plot in every which way possible and does so exceptionally masterfully. He already has three side-stories that introduce main plot elements because his series isn't a normal one, and it has its own way of presenting a brilliant world. The strongest point is that he'll teach you things even while you just read it for pure enjoyment in a crazy fantastical story whose match you might not find in any other novel on this site including all the CN's, LN's, and KN's. However, it's definitely the case that if you pore through every page and try to figure things out more, then you'll be rewarded and you'll notice tons of tiny details that are subtly introduced and never outright said until they might come into play 5-10 books later.
There are many times when people stick with something after an unextraordinary start and see it become truly amazing. And they really wish that they could find the right words to convince other people that they'd truly stumbled upon something amazing. The anime for Index sucks in comparison. If you've seen the index/railgun anime and concluded that this series isn't very good, please reconsider and try reading the novels. The novel is primarily interesting because of the motivations of our protagonists and their underlying principles and how they clash in a gigantic clash of ideals. That is completely discarded for action in the anime. This makes the anime fun for people who've read the novels, but unfortunately it doesn't work the other way around. If you agree with some of my other reviews, please give this series a chance. I feel frustrated that it isn't popular. It deserves to be much more popular. If it weren't for its underwhelming anime and for the fact that it was written before LN's were written in such a way that considered how easy it was for anime to adapt them, it would have probably become one of the most popular series in the world.
The books aren't too long, and they start off way better than the anime. There are a few turning points in the series. Starting from the epilogue OT 6 the story improves dramatically. At the beginning of OT 13 Index truly gets into its own, this is where the season 3 material would be if it ever happens... From there on it's better than anything else I've read. Volume 20 and on is another improvement. And at the end of NT 6 and on is another dramatic improvement it improves in quality again. NT 17 and on is an even more dramatic improvement. There is no filler, no wasted content. Only true genius. Please give this story a try if you have the free time--you likely won't regret it.