The one who aspires to become a Librarian, and the one who's a Walking Library. Best waifus for Book Lovers~
Myne and Index share the same voice actor. Once I realized that the heroines of two of my favorite anime (Ascendance of a Bookworm and A Certain Magical Index) are voiced by Yuka Iguchi, something in mind mind clicked. It felt perfect that they have the same voice because their characters do have a connection, even if their personalities are vastly different.
I just looked at her voice acting resume, she plays many different roles. In this post I'll only talk about her Index-like roles, though~
MINOR SPOILERS for Both Series
For those new to either series:
Ascendance of a Bookworm follows Orano Motosu, a librarian who died on her first day of job and had a chance for a second life in the body of Myne: A young sickly girl in a world without books. She decides to make her own books to become a librarian of her own library.
A Certain Magical Index is a Science vs. Magic story in which both sides developed their own form of super powers. The story follows Touma Kamijou an Esper from the science side, who has the ability to cancel anything supernatural after a chance meeting with Index, the girl who has 103,000 Grimoires in her head. This starts the Touma's never-ending involvement between both sides of conflict.
As you can see, from their concepts alone both girls have something in common: Books!
While Myne aspires to read books and (when she didn't find any,) write them. Index have already memorized more than a hundred thousand of them. Myne aspires to become a Librarian of a huge Library, Index is an actual Library with a human interface, and you have to be on good terms with her to even access.
In short: Myne will do anything to become Index!
At least, that's how I see her character after watching both seasons of the anime!
The more I think about them the more contrast points I can find with them. Index has a perfect memory so she doesn't need to re-experience anything. She also doesn't express a desire to obtain a new knowledge and she's is useless with modern technology. Myne on the other hand has better-than-average memory, she always strives to learn new stuff and she's basically the inventor of the world she finds herself in, mixing knowledge from our world with the fantasy stuff to create tools that help everyone.
I might make a list of those contrast points when I re-watch both series.
Another thing I find interesting is that both of them have a hidden dark personality:
Index has John Pen Mode a magical A.I. personality implanted in her by the church to protect her life whenever she's in danger. John Pen Index has no feelings and is only optimized to save the Grimoires in her head without taking her friends lives into consideration.
Myne has the devouring an illness that becomes stronger under stress, in the extreme cases, her mind stops working while her instincts take over. It's not another personality but it shows what she's able to do for her friends and books if her morality filter isn't working.
I wanted mention these dark sides because Yuka's voice in them is so different. So eerie! Just watch the clip mentioned above of Myne or John Pen Index and compare it with any normal scene with them, it's scary! It's brilliant!
Finally, I want to mention that one of Yuka voiced characters: Maria Takayama from Haganai is also a nun. She's a more spoiled version of Index, and that's saying something!