I guess the little backstory was necessary. Not super exciting but necessary to fill the gaps.
Still, I have lots of questions on how this world works. What are these books exactly, how does the magic work... is it like Naruto and the chakra? Star Wars and the force?
How is the dude of the chains in one piece after receiving a slash from that demon sword? I would've expected him to be cut in half, if not, surely die from the impact.