Endro!
In the land of Naral Island, a land of magic and swords, humans and monsters live together. Once upon a time, there used to be a terrifying Demon Lord, but long, long ago the first Hero defeated the Demon Lord. The Demon Lord would revive again and again throughout the ages, but every time a Hero would appear to defeat it... Now these young girls attend an Adventurer's Academy to prepare them to defeat the Demon Lord that will one day rise again. This is the beginning of a laid-back fantasy life with no sign of the Demon Lord for these four who hope to become a party of heroes. Source: crunchyroll
NAN0 is JPN BD Remux+Astral and PGS Kawaii is KnK+Astral (Restyled CR with OP/ED translations)