The Unending Dungeon

The Unending Dungeon or Infinite Labyrinth is the a location of the Ore dake Irerukakushi Dungeon.

It's a Hidden Dungeon where Noir learned how to exist and invade with his Great Sage skills. The remarks of the four layers of Ghosts suggest that 200-300 years ago. It is Olivia, not Noir, who first went inside after it was sealed.

It is located inside a cave located 15,000 meters southwest of the Royal Capital, in the mountains.

In addition to locating the entrance, you need to push the rotating wall on the left to reveal the stairs to a massive iron gate. No matter what kind of magic attack one summoned, it didn't seem like it'd budge in the least. It is also necessary to recite the required spell: "「The Hidden Dungeon only I can enter. Secretly becoming world strongest!」".

The Floors of the Dugeon are full of rare monsters and creatures, as Noir noticed after he saw its slimes, because the golden ones were pratically unheard of.

The Floors of the Unending Dungeon can simulate different environments, as the 7th and 17th Floor have fake suns, and the 9th and 11th Floors were similar to a ocean and a volcano.

The Unening Dungeon can be very dangerous, because even its "bonus level", the Forest of Gold, is full of dangerous creratures. As Noir progressed through the Floors, he noticed the monsters were getting stronger.

Besides monsters and creatures, the Dungeon is full of illusions and traps, as the Death Chains that sealed Olivia, and supposed humans like Huck, Uuck and Auck in the 8th Floor, the audience in the theater inside the Path of Laugther, Son and his battalion in the Path of Anger, the audience and host of the fighting arena in the 13th Floor, Fake Olivia in the 15th Floor and the Sisters of Selene in the 16th Floor.

In order to go through some floor, the seeker must complete some trails, like strengthen a weapon in the 12th to open the pathway to the 13th Floor, defeat three adversaries in the fighting arena in the 13th Floor to open the gate to the 14th Floor and the 14th Floor Trials. This tasks can be a trap, like strengthen a weapon that will be used by a adversary against it's former user in the next level.

Known Floors
1th Floor: Golden Slimes full runner. 2th Floor: Several rooms with monsters and traps, one of which is Olivia, whose limbs are chained and crucified.

3th Floor: Open hallway with a Dead Reaper.

4th Floor: Hall of the Dead with Ghosts of former dungeon seekers who died in the Unending Dungeon.

5th Floor: Giant Beasts:


 * Giant Pincer Ants
 * Giant Python
 * Giant Toad
 * Tigerson

6th Floor: Army of Sextuple Zombies. 7th Floor: Forest of Gold full of rare monsters and bugs:


 * Golden Rhinocerus Beetles
 * Silver Stag Beetles
 * Golden Pillbugs
 * Silver Wolves
 * Killer Tree
 * Dory
 * Golden Bee

8th Floor: Maze of Corridors with Ogre Hag and Dark Box.

9th Floor: Submerged Hall with tons of fish, sharks, and monsters:


 * Bonefish
 * King Octopus

10th Floor: Hallway with Stone Dog and Three Paths: Path of Anger, Path of Sorrow and Path of Laughter.

11th Floor: Volcanic Chamber with monsters:


 * Magmafish

12th Floor: Room with 48 talking weapons, including Noname, and corridors and rooms full of monsters:


 * Mudmen
 * Brown Bears
 * Red Ravens

There is a hidden stone pedestal that, after placing the chosen talking weapon, it absorbs the weapon, revealing the pathway to the next floor.

13th Floor: Fighting Arena with a host and audience where the seeker must fight against three adversaries:


 * Bernard Tiger
 * Armored Warrior
 * Red Lizardman with Noname

14th Floor: Different trials for a single, two, three and four seekers:


 * Single Person: Path full of snakes, spiders, lizards and black bugs that the seeker can't kill, otherwise the seeker must restart the path


 * Pair: Amber-colored room full of Pygmies

15th Floor: Large stone monument with Fake Olivia trapped.

16th Floor: Corridor with flying bricks and Goblins

17 Floor: Island Chamber inhabitated by a tribe

Trivia

 * This is the place where Noir meets Olivia.
 * The 9th and the 10th Floors were switched in the manga.