Mama Yuuyuu

An era of peace between the hero and demon lord is upon us! In this peaceful world, the hero Corleo is nothing but an empty suit. But one day, a hero and demon lord from another world appear before him! How will Corleo deal with the chaos these invaders bring to his world?! A new type of fantasy epic now begins!
(Source: MANGA Plus)
Notes:
-Volume 3 contains two extra chapters.
-Volume 4 contains three extra chapters.