Mana (mah-nah) is the energy that all living creatures emit, it powers their bodies and mind. Through various techniques, mana can be used to cast magic.
Every living thing has a soul where mana is created. When it exits the soul it interacts with a mind and becomes claimed by it. Once mana is claimed it cannot directly interact with any other mind and can only listen to comands of a mind by which it was touched first. Every living creature's body and mind needs mana to sustain itself, excess mana is emitted outside of the body. While there, it creates an aura which transmits present state of the mind, and when condensed enough it creates a mage armor which can stop casting foreign spell on everything inside the armor. Body of every living thing emits mana in regular intervals.
Mana can pass through solid matter like through air, however every object has mana resistance that allows how much mana can pass through it and how much can stay inside. This rule includes every living being too. Although it is possible to raise mana tolerance while decreasing mana resistance of a living body through mana tempering.
Most living creatures can sense foreign mana which detected the presence of others being near them. It would be difficult however if the creature has a keen sense of detecting mana. There is a technique to conceal the presence of oneself by hiding behind a crafted barrier that controlled the mana leaving away from their body. Creature that has slow mana flow would have an easier time controlling it since they only had little mana to look after. For those with fast mana flow, the technique will be extremely hard to apply. For most mages, this technique is an essential to learn.
Each living being has a Mana Pool, a place within the soul where mana is produced and accumulated. The larger the Mana Pool is the more mana there would be ready to cast into spells. When mana is consumed it will regenerate by itself, but speed of this process depends on soul's mana regeneration ability. Additionaly it is imposible for the owner of the Mana Pool to exactly messure how much mana "units" are left in it without expending it all to a specific measuring device. Although everyone can tell "on the go" how much of their Mana Pool is filled.
In order to use magic, the user must transfer mana from their soul to their target. This technique is known as Mana Flow. Mages that can efficiently gather mana fast enough would be able to cast their spell faster to the point they can even cast several spells at once. Mana would then be woven into a specific 3D spell pattern which requires a lot of precision and control. The ability to weave spell is directly related with the ability to cast magic spells. Mages that can weave well can learn how to execute new spells faster than those that could not weave well.
Good weaving leads to spells being more potent, taking less time to cast and being better overall(like a carefull writing makes information easier to read). The ability to gather mana to cast spells and the speed of weaving spells also tie in with the speed of casting spells.
To cast a spell it is required to know the spell pattern and to have specific type of mana(argel can only use augmentation spells and elibu can only use transmutation spells, unless they have pure mana which allows to cast not only augmentation and transmutation magic but also arcane magic).
After the mana is weaved into a meaningful pattern, the mana would no longer be just drops of individual energy but will condense itself into a spell, which will be signaled as almost unnoticeable small flash of mana from the spell pattern. The activated spell pattern would then keep creating a reality altering phenomenon until it consumes all its supplied mana(including mana used to weave the spell pattern), the spell pattern or the reality altering phenomenon are significantly damaged(to the point of not being able to repair eachother), or the reality altering phenomenon encounters a very strong interference with a similar but much stronger spell.
Weaving mana is not done with the body but with the mind so it is possible to weave several spells at once. Even though it is not required many mages do small movement or gestures while weaving spells.
The ability to wield a spell is called spell control.