Apologies, long rambling comment here.
"The Boss here doesn't want to be one." Exactly, Hod really doesn't like the killing. She also has a few regrets, but those are from another life. She is very meek indeed, and holds therapy sessions for her Assistant Librarians.
Also, technically, in regards to the boss theme thing: Yes, technically these are all boss themes. Though, Aside from the Mili song accompanied Boss fights, we usually play as the bosses.
Below is a sort of rough breakdown of the game's general idea, and may technically be a spoiler in regards to going completely blind into musical reactions.
The floors of our library are all run by a head librarian and their assistants. From lowest floor to highest:
Malkuth, Head Librarian of the Floor of History
Yesod, Head Librarian of the Floor of Technological Sciences
Hod, Head Librarian of the Floor of Literature
Netzach, Head Librarian of the Floor of Art
Tiphereth, Head Librarian of the Floor of Natural Sciences
Gebura, Head Librarian of the Floor of Language
Chesed, Head Librarian of the Floor of Social Sciences
Binah, Head Librarian of the Floor of Philosophy
Hokma, Head Librarian of the Floor of Religion
And Lastly, Roland, a random guy and one of our 2 primary protagonists, the Head Librarian of the floor of General Works.
There's also Angela our other protag, but she is not in charge of a particular floor, as she is in charge of the library as a whole.
The game consists of various individuals from all around 'The City' entering the library and trying to obtain books of knowledge, in order to do so, they must defeat a set number of the floor's head librarians. If they fail and die in battle, they become the books of knowledge relating to their lives. For the most part, we are the technical villains of the story.