Okutama Kojin Meikyuu - Shinshoku shite Kita Isekai Meikyuu奥多摩個人迷宮 ～浸食してきた異世界迷宮; Okutama Personal Labyrinth ~ Erosed Different World Labyrinth; Okutama Personal Labyrinth ~ The Encroaching Otherworld Maze

"Dungeons are invading Japan! Conquer dungeons of swords and magic with 'modern science'!" A dungeon suddenly appeared in the modern world. And the witches by the magic essence "mana" overflowing from the erosion mouth. A new occupation "Adventurer" is born.