Therese recalled what they have found out about the mysterious Ancient Book. When she tried to appraise the item based on its outside appearance, she can tell that it was most likely two centuries old.
She had seen many books that were around that old so she was confident about her estimate of its age. Aside from that, the mysterious method used to bound the book was something that a cult about two centuries ago has done before.
No one knows how it was being done but the book they make will always exude a mysterious aura as if it was cursed. Unfortunately, the cult has been completely eradicated now so no one knows the method to create these books.
As for its content, it appears to be just an evil ritual of some sort, and anyone who tried to practice it would have their mana taken away by an evil god.
"Interesting… Are you telling us that the book was bound by a human skin?"
"Aside from that, it contains a Mana Art as well?"
