Intai Shita Saikyou Ansatsusha wa Henkyou no Shima de Shizuka ni Kurashitai Manga

A world that regained peace after the Demon King vanished. On a remote frontier island, Shinenai, the owner of an item shop, lived a lively yet quiet life alongside his wife Luna and daughter Rin. Then one day, triggered by the appearance of a "dungeon" on the island, the Royal Knights and adventurers from all over come swarming in. At the same time, fate and ties from the past creep up on the family——. The quiet struggle of a man who once secretly buried so much, all to live with his family‼