地下室ダンジョン　～貧乏兄妹は娯楽を求めて最強へ～ (Associated Names)

One day, dungeons appeared all over the world. The creatures that sprung up from the dungeons laid waste to the nearby humans and animals. However, the UMAs, commonly referred to as monsters, that emerged from the dungeons seemed to lose their power as they left the dungeons. Soon, they were quickly eradicated by the technologically…