The rank of mages.

Similar to warriors, there are different ranks of mages starting at true mage, advanced mage, lord, and overlord.

True mage have an understanding of how their magic works and can apply it without using a spell made by others. They are capable of reaching their own spells and powers.

Advanced mages has a more in-depth understanding of their magic, advanced mages are capable of using more power in their spells and increasing the complexity of spells.

Lords have a quantitative change in their magic, after reaching a certain point of understanding, mages form a core in their bodies, this core allows them to start storing magic instead of using the ambient mana, this allows faster casting and much more powerful spells.

Overlords are the peak of mages, capable of forming multiple cores for multiple types of magic. This is a rank that most mages never even dream of reaching because of the increased difficulty in forming cores. At this point, the amount of mana that can be stored has reached the point that it starts infusing into the body of the mage. Massively increasing the amount of power they have available to them. This is the highest point a mage can reach before up tiering.