Manga wo Yomeru Ore ga Sekai Saikyou: Yome-tachi to Sugosu Kimama na Seikatsu

The world I was reincarnated into was a world that enables one to use magic after reading a Grimoire. Inside the Grimoire lies a manga, and this world's people would take around a year to read one Grimoire. However, for me, it would only take one hour.

Now, the six-year-old me can interpret and understand all kinds of Grimoires, and thus became the World's Strongest Master Sage.

(Source: Paichun Translations, edited)