Zero kara Hajimeru Mahou no Sho (Grimoire/Book of Zero) is a story set on a time where witches are being hunted and killed. In their world, Year 526 of the Liturgical Year, there are also people who are being born as half-human, half-beast called Beastfallen, who are also being hunted by the people and the only one that the people believe and rely on is the church.
In my own opinion, this anime is the story of Zero, whom everyone referred to as “the witch” on Re:Zero kara Hajimeru Isekai Seikatsu, since there’s a few or none that was exposed about the witch in the previous anime. How come that a witch so powerful not being talked about in the anime, right? I think this is a clever move to have this novel of Kobashiri Kakeru be made into an anime for everyone to enjoy.
The first episode is somewhat an introduction, for you to see what their world looks like. It also shows how come a Beastfallen who hunts witches be associated with the witch, Zero. On the end of the first episode, there is also a guy in a tracker suit that reminds me of Subaru. Is he also from the modern world transported into another dimension?