Great Elroe Labyrinth

The Great Elroe Labyrinth is the largest labyrinth in the world, connecting the continents of Daztrudia and Kasanagara underground while having an ocean above it. It is home to a myriad of monsters that often have the name of the dungeon attached to their name. This is the first dungeon the protagonist awakes in after her reincarnation.

Background
The Great Elroe Labyrinth is an important connection between Daztrudia and Kasanagara, as the ocean is impassable due to the presence of water dragons. While in these days teleportation circles are also an option, the Labyrinth is still the only land connection between the two continents.

The Labyrinth is in total far larger than Hokkaido.

Plot
Two characters were reincarnated inside of the labyrinth, one as a nameless Small Lesser Taratect and the other as an Earth Dragon egg. Fortunately for the dragon egg, she was brought out of the labyrinth by a group of adventurers, while the spider reincarnator has to live in the harsh environment of the labyrinth.

Layout
The Labyrinth is separated into four different levels of depth; the Upper Strata, Middle Strata, Lower Strata, and Bottom Strata.

The Upper Strata is the highest floor of the labyrinth and the area that the weakest monsters inhabit, although nearly all of them are poisonous. People that pass through the Labyrinth to cross from Daztrudia to Kasanagara will travel only through this layer, as any lower ones would be too dangerous for humans.

The Middle Strata of the Labyrinth sits between the Upper and Lower strata. The entire area is covered in flowing, red-hot magma.

Below the Middle Strata are the Lower Strata and Bottom Strata. Compared to the Middle Strata the environment is less hostile, being a simple cavern landscape, but instead are swarmed with many powerful monsters that are incomparable to the Upper and Middle Strata. There are some monsters that are not powerful in these strata, such as the snail-bug.

Ecosystem
Some of the monsters of the labyrinth, such as small rock turtles, basilisks, and frogs are able to digest the rocks of the labyrinth. Plant-type monsters, such as the parasitic flowers, are likely able to extract energy from labyrinth in the same way, and provide a food source for the herbivores such as deer.

Known Individuals

 * The Nightmare of the Labyrinth
 * Queen Taratect
 * Fire Dragon Rend
 * Earth Dragon Araba
 * Earth Dragon Kagna
 * Earth Dragon Gehre
 * Earth Dragon Fuito
 * Earth Dragon Gakia
 * Water Dragon Krag
 * Earth Dragon Ekisa
 * Sariel

Upper Stratum
Creatures in this layer seem to be weaker than the other layers, most of them also specialize in inducing status effects.
 * Small Lesser Taratect
 * Elroe Frog
 * Elroe Randanel (three intimate friends)
 * Elroe Peckatot (Penguin)
 * Elroe Basilisk
 * Small Rock Turtle
 * Elroe Ferect (Centipede)
 * Elroe Baladorado (Snake)
 * Elroe Kolift (baby earth wyrm)
 * Elroe Mowajitz (Deer)
 * unnamed bat monster
 * unnamed 6-legged wolf monster
 * Fenegrad
 * Elroe Wiris (flower)
 * Water dragons

Middle Stratum
As the middle layer is filled with lava pools most of these creatures have fire related attacks and fire resistance capable of swimming in the lava.
 * Elroe Piek (Red dog)
 * Elroe Geafrog (Elroe Frog's evolution)
 * Elroe Debegiad (Round bug)
 * Elroe Gunerush (Seahorse)
 * Elroe Guneseven (Catfish)
 * Elroe Gunerave (Eel)
 * Elroe Gunesohka (Fire Drake)
 * Fire dragons

Lower Stratum
Most of the creatures in this layer are very dangerous compared to the ones from the upper layers.
 * Elroe Greym (Mouse)
 * Finjicote (Bee)
 * High Finjicote
 * General Finjicote
 * Queen Finjicote
 * Elroe Gastruch (Snail-Bugs)
 * Elroe Greshigard (Mantis)
 * Elroe Daznatch (limbed fish)
 * Elroe Kohokoro (Pill bug)
 * Greater Taratect
 * Anogratch (Monkey)
 * Bagragratch (Giant monkey)
 * Elroe Baraggish (Giant snake)
 * Earth dragons
 * Frog prince (super-evolved frog)
 * Giant metal pond skater

Bottom Stratum
The most dangerous place in the dungeon due to being inhabited mostly by Earth Dragons, and being the place where the Queen Taratect can be found when she's not wandering around the Labyrinth.
 * Queen Taratect
 * Earth Dragon

Wandering
These creatures move around the different layers of the labyrinth.
 * Arch Taratect
 * Puppet Taratect
 * Queen Taratect (when laying eggs)
 * The Nightmare's Vestige

Features
The Daztrudia entrance is surrounded by a fortress. The fortress doubles as a breakwater for a demon invasion from Kasangara, and as a barrier to trespassers and escaping monsters.

Trivia

 * Elroe Randanael could be a reference to the "rule of three" trope.
 * Elroe Piek could be a reference to One Piece's Akainu whose nickname means red dog and has magma related power.