Hentai.net: Portable

(Anime & Manga) Genre: Historical Fantasy, Action A boy becomes a demon slayer to save his demon-turned sister. The anime’s Ufotable animation is legendary (especially the Entertainment District Arc). The manga is complete and fast-paced.

It is the "grandfather of Isekai." The world-building is dense, the magic system is detailed, and the character growth is realistic. Rudeus starts as a disgusting person, but the show forces you to watch him improve. hentai.net