A Pond, Comrades, and a Seashell - S1.E8

Norotei learns that Zatoh is a 'book eater', a monster who can devour books gaining the knowledge and power of the person concerned. When Zatoh consumes Lumion's book Norotei becomes so angry that she becomes serious about fighting for the first time. Meanwhile, somewhere inside of Zatoh's soul all of the books he has consumed begin to rebel against him.