Chikashitsu Dungeon: Binbou Kyoudai wa Goraku wo Motomete Saikyou e

A dungeon suddenly appeared in the basement of the shabby house where two poor siblings, Fuyuka and Haruka, lived. Delving into the dungeon every day to hunt for the treasures and meat that monsters drop, before they knew it they have become the strongest dungeon explorers in Japan...!? (Source: Shueisha, translated)