levelling up in an exclusive dungeon

Hunter Kang Jin-hyeok has been D-rank for years. His days were spent barely scraping by with part-time jobs, unable to level up due to the hunting grounds being controlled by major guilds. One day, a dungeon appears in his room. "This is… a dungeon?" With the dungeon now in his possession, Jinhyuk begins to successfully hunt, level up, and gradually grow stronger… "Just wait and see, you major guild scumbags who looked down on me! I will become stronger with this dungeon!"