The characters run the gamut from "not offensive" to "is also on the show." That Dalian, resident plucky sidekick, manages to have a personality largely through catty insults and being easily bribed by sweets is a testament to the lack of sophistication on offer. Even the main character tends to fall into a vacuum of "main character," from which no discernible personality emerges that isn't at the whim of the plot. Honestly, the most interesting episode, in terms of character, is probably the one featuring the Libricide officer, who's relationship with his do-nothing plucky sidekick is the sort of abusive I'm sure could be written by fanfic writers as being code for some kind of dom-sub thing, but that could just be me.
So, the characters are uninspired. The plot is okay. The idea of magical books that in some backfirey way grant the wishes of the innocent and not so innocent is the kind of thing that lends itself to interesting plots. By the exact same token, however, giving the main characters seemingly unlimited access to a whole library of magic books means that any threat or problem, once sufficiently established, usually goes away as fast as it shows up. When the once-an-episode "pull books out of the sidekick's chest cavity" canned animation plays and Huey reads a passage from the "shoot indiscriminate plot-erasing lasers" book, the story tends to lose any sense of stakes.
Overall, it's a serviceable anime, if relatively bland. Coming from the same studio that brought us Evangelion and Gurren Lagan, I suppose a part of me was expecting a show with a bit more bite, but it's not a bad way to eat up a portion of time, generally.
