Mansen Maou Shoujo Ena-sama

Summary

In the land of Glengard, the realm's 666th Demon King, Fienalia Glengard Flamveil...is bored. With no challenges to excite her and all of humanity long since subjugated, she's off to find a new world-any world!-to conquer...and it just so happens that Earth is next on the hit list! But when "Ena-sama" meets Kento Sugitani, an aspiring manga artist, it seems she might have found a new hobby more interesting than world domination. What is a demon lord to do but enroll in a manga school herself?! (Source: Yen Press)