Adventurer's Guild:
F - No trim
E - Iron trim
D - Bronze trim
C - Silver trim
B - Gold trim
A - Platinum trim
S - Scarletite trim
Sprits:
As a spirit's power increases, so does their intelligence.
Class 6 - Incapable of thought, like an object
Class 5 - Capable of receiving commands and producing an output, like a computer
Class 4 - Capable of thinking for themselves and adapting to new information, like an animal
Class 3 - Capable of human thought and language, below average human intelligence
Class 2 - Capable of complex thinking and understanding, average human intelligence
Class 1 - Capable of highly sophisticated thinking, above average human intelligence
Class 0:
There can only be 5 class 0 spirits per type, each one with different abilities forming what is known as the five orders. Each has their own philosophical understanding of the world, called by some divine knowledge, as well as being incredibly smart.
True - has abstract powers that work on a conceptual level and are hard to understand.
Sacred - has seemingly unending energy reserves and the strongest level of power in their type.
Complete - has a variety of techniques at their disposal and can suppress other spirits powers.
Imperial - has the ability to control other spirits of their own type and borrow their power.
Eternal - has an indestructible soul that will continue existing forever.
Most spirits rely on their anchor to support their mind. Although their power will remain the same, a spirit may have their intelligence level reduced depending on what their anchor is. The only exception is class 1 and class 0 spirits, whose intelligence remains the same regardless. For example, if a class 2 spirit is anchored to an object, it'll be capable of responding to commands by the user and have useful functions, but nothing more.
Human - no reduction in intelligence
Animal - reduction of intelligence by 1 class
Plant - reduction of intelligence by 2 classes
Object - reduction of intelligence by 3 classes
More information will be added as the story continues.