Dungeon no Naka Hito

Clay was trained by her father to be an expert member of the thieves’ guild. Since her father disappeared three years ago, she’s been using her skills to search for him in a dungeon filled with goblins, a Minotaur, and all manner of other dangerous creatures. When Clay reaches deeper than anyone ever has before, she meets the caretaker of the dungeon. To her surprise, Clay is invited to join the staff! And thus begins Clay’s new job–to learn the inner workings and behind-the-scenes secrets of the dungeon from the inside. [Seven Seas]Original Web Manga