In the world of battle magus, there is an intangible energy called mana which is present in everyone and thing in the world, living or not. Using this power, wonderous things can be achieved, but people who can freely harness the power are rare, with one appearing in every hundred thousand or so, and those people are called mages.

There are two categories of mages :

Conjurer: These are individuals with the ability to manipulate the mana in the environment with the help of their innate mana to cast spells. Unlike fortifiers, they are unable to strengthen their bodies with their innate mana even though they possess it. But in return, they can cast larger scale and stronger spells more frequently than fortifiers. 

Fortifier: these are individuals who cannot manipulate the mana in the environment and focus on using their innate mana to strengthen their bodies, giving them superhuman strength and speed. Like conjurers, they are able to use their innate mana they are able to conjure spells but their limit of uses is low as it drains their mana faster.

Within the ranks of the mages, there are rankings from weakest to strongest:

Novice

Apprentice

Sorcerer

Mage

Greatmage

Archmage

Ascendant

Transcendent

Magus

With apprentice being the weakest and Magus being the strongest, with ranks determined by mainly mana capacity. A novice would have a newly formed and weak mana core and a small amount of mana stored within, while a magus would have an extremely developed and strong one with a massive amount of mana within.

The ranks have sub-ranks, namely: Low, Mid, and High.

Mana affinity: the density of one's mana is what determines the talent of an individual, with mana density being determined by the color of the individuals innate mana, namely;

Blue

White

Silver

Platinum

Gold

This also applies to magic beasts.

Spells:

these are instructions or commands given to mana that produce a desired effect. A mages ability to cast a spell relies entirely on how well they can visualize the desired effect and result. This would mean experienced casters "build" spells by layering these instructions, possibly even combining multiple principles for complex effects.

Magic Affinity:

Every mage has an affinity for a branch of magic, of which there are four;

Arcane magic

Astral magic

Dark magic

Elemental magic

Each branch is sub-divided into other specific deviations of that type.

Arcane; which is the rarest, deals with the manipulation of the fundamental forces of the world. e.g Time magic, reality magic.

Astral; is the second rarest, is a branch where magic with no particular direction or specification is categorized. e.g Rune magic, summoning magic.

Chaos magic; A branch of magic that deals with the darker forces of the world. It is reasonably common but looked down upon for it is innately evil in nature. e.g Necromancy, blood magic.

Elemental magic; the most common branch of magic that deals with the forces of nature, wind, water, fire and earth. Each has its deviations, for example under fire you have lightning and under water, you have ice.

Typically a mage has affinity for one type and branch of magic, but like in everything in life, there are special cases.