So there is a need for me to explain a lot of things based on how the book is going...

Let's start from the biggest to the smallest

Cosmology: The Cosmology is not just a world or a universe it is the wheel that drives every universe and worlds, be it mortal world, celestial world or primordial worlds. In the Cosmos there are basically five planes.

What are planes?

Planes are the spaces were a universe or galaxy occupies, and it is possible for more than one universe to be on a plane; You know that's called a multiverse within the same timeline but different people in it. As long as it is the same timeline, the same person can never exist there.

But you don't need to worry, we won't be diving into timelines for now.

Let's talk about the monsters first

Monsters(according to Therut) are classified into two main kinds.

Field Monsters: Monsters that are found in forest and deserted plains and have come to make that place their habitat

Dungeon Monsters: Monsters that are only found when dungeons appear. These kinds of monsters are extremely strong compared to a field monster because they have been exposed to a larger amount of cosmotic energy thanks to the dungeon itself, this cosmotic energy doesn't only strengthen them, it gives them a core and the intelligence to adapt and evolve.

Hence the higher the difficulty of the dungeon the greater the threat that they pose to not only humanity but other forms of existence.

Hence the dungeons are grouped into difficulties while the field monsters and areas they can be found are grouped into tiers.

Dungeon

Difficulty: level 1 ~ level 10

(However dungeons of higher difficulties will soon begin to surface but humanity will first not understand this)

Field tiers: tier 1 ~ tier 9

Field monsters are always without cores but their carcasses have a lot of use.

Dungeon monsters are more valuable, their cores have several uses and phenomenal such titles, Perks and skills are only granted due to and outstanding achievement in a dungeon.

Monster cores.

Monsters cores are classified according to colors.

Blue monster cores - Dungeon level 1 ~ 2

Red monster cores - Dungeon level 3 ~ 4

White monster cores - Dungeon level 5

Green monster cores - Dungeon level 6

Grey monster cores - Dungeon level 7

Yellow monster cores - Dungeon level 8

Orange monster cores - Dungeon level 9

Purple monster cores - Dungeon level 10

Cream monster cores

Brown monster cores

Black monster cores

Colourless monster cores.

Classification according to Earth.

I'm Earth, dungeons are known as gates, Heroes are known as Hunters.

And the rank goes from

F rank

E rank

D rank

C rank

B rank

A rank

S rank

Then we have those that transcend common sense.

Disaster rank

Catastrophe rank

These two ranks are more of a destruction than actual ranks– and cam clear all the gates singlehandedly except for few A ranks gates and S rank gates.

The ranking of gates are equal to the ranking hunters, except Disaster and Catastrophe rank gates that are YET to appear.

In earth, hunters do not have a system, they do not hear the voice of the world and do not need to receive quest. All they need to do is hunt monsters. 

Hunters can get skills from rune crystals which can often be found in monsters. 

There are two types of crystal.

An ordinary crystal and a rune crystal.

A rune crystal is found when a monster is killed, however it isn't everytime, for some monsters that are low leveled– there might be no rune crystals. 

The second kinds of crystal is ordinary crystal, which grows like minerals in the gates, they can be harvested and used go reinforce and forge hunter's weapons along with some other fantastic technology advances.

That will be all for now but expect more updates as the story goes on, please feel free to comment as much as you like this silly hunter is a talkative.

I wish you a well journey into this wonderful world