Hidden Dungeon Only I Can Enter (Manga) Vol. 12, The

THE FINAL SHOWDOWN!
Thanks to the efforts of Noir and Luna, the serial killer running rampant in town has finally been captured! But now a new, more personal threat is looming on the horizon.
The copy of Olivia Servant that was created by the Cursed Death Chains has broken free of the Hidden Dungeon and is looking to wreak havoc on the outside world! Will Noir have what it takes to face this imposter and save his imprisoned master once and for all?! Find out in the thrilling conclusion of The Hidden Dungeon Only I Can Enter!
The final volume!
Series Overview: Noir Stardia, lesser son of an even lesser noble, just lost his job.
Without a penny to his name, he decides to enroll in the Hero Academy and improve his career prospects. But he’ll need to get a lot stronger to pass the entrance exam. So Noir seeks out a hidden dungeon—a legendary labyrinth filled with strange beasts and rare items—where he can train until he’s powerful enough to change his fate!