Book by Hajime Kanzaka, Rui Araizumi

When Lina loses her magic, she travels to Mine where she meets a mysterious priest who agrees to help her restore her magic provided that she help him recover the Clair Bible.

Guided by Xelloss, an agent of the Greater Beast Zelas Metalium, Lina Inverse and her crew make their way to the heart of Dilse Kingdom—a country with many hidden mysteries—including the Claire Bible. While it seems fate has deemed that Xelloss take Lina to those manuscripts, she's not sure what his real plan is...but she really wants that Claire Bible, so she'll do whatever it takes!

Hey, here’s a question. When demons are transforming into bigger, badder demons, otherwise temperate towns are getting unseasonal snow, and you’re catching sight of your own doppelgänger... that’s a bad sign, right? And when it all seems to be pointing you toward Sairaag—basically the world’s nexus of bad magical mojo—that’s a REALLY bad sign, isn’t it? But I know from experience what happens when you try to say no to a plot like this, so... let’s just get it over with, shall we?