Saikyou Shugosha to Eichi no Madou Hime: Shinigami no Chikara wo Motsu Shounen wa Subete wo Houmuri Saru

To protect the Angel, the strongest Grim Reaper steps in— The Brugel Kingdom, known as the land of knowledge, boasts numerous libraries. Within the royal capital lies the Forbidden Library, which houses only cursed books and texts containing abilities that could destroy the nation if misused. Kum...

Source: MyAnimeList