Magical power

Magical power, also known as orgone, is the energy magic casters draw upon to cast their magic. Although all living things have a certain amount of orgone, the vast majority of it is spent on maintaining their life. As such, mages often require external sources of power to cast. 
External sources of orgone are extremely varied. Most sources are associated with particular schools of magic. The most notorious are natural magic and mana magic; but there are many others: spirit magic, death magic, blood magic etc. 
The natural amount of excess power a person has is an important factor of the capacity for one to become a mage, as it is the main determining factor of whether or not one can learn to cast any magic. Natural excess power is known as magical potential. Potential varies widely across individuals, but some species are more likely to have high potential. The parentage of a child is also a crucial factor in its potential, a child born to two mage parents is drastically more likely to have a high potential than an average child. Elves, in particular imperial elves, have a particularly high naturally occurring potential whilst dwarves have a virtually non-existent potential. Some non-anthropoid species have exceptionally high naturally occurring potential, for instance blue-tail caramiso.