Kagami no Mukou no Saihate Toshokan

Wallace, the head librarian of the "Library of the End," has no memory. And what lies inside the forgotten library in the furthest end of the world are only a taciturn maid and the "Magic Monsters of the Books" that he just can't get through. The library gets no visitors and, as the head librarian, Wallace cannot leave. So he lives his days in relative solitude, unable to discover his past. And then, one day. He met Lucia, a witch apprentice from the "Village of the Beginning," through a mirror. This is a story of them, a lonely and gentle fantasy story; a fairytale that will not be passed down to anyone.

[Official Website](https://dengekibunko.jp/title/saihate/)