Green Magic is an art which was discovered only a few centuries ago by the illustrious Al Abassi. Its an unique discipline and form of magic which rather than to draw upon aether directly, instead works by gathering energy from the casters sorroundings or from other external sources of nature. When harnessed this allows the caster to use spells which attempt to manipulate that which already exists to their liking, as opposed to create something new.
In comparisons to the arts of black and white magic, green magic is practised only very rarely, and primarily by Al Abassi shamans, who use the magic of nature to heal both nature and their own kind. Its green magic that is the reason for the immense walls of flora that sometimes sorround Al Abassi settlements, to keep predators and unwanted guests away from their sanctums. The Al Abassi, disillusioned by the ways of black magic, which they considered to be an affront to the Great Beasts developed Green Magic over the course of a century, their shamans tirelessly working towards the project and it was their close bond with nature that eventually lead to a breaktrough, because they found that the world itself had abundant energy which could be borrowed by a skilled mage.
Thus was the quintessential cornerstone for Green Magic developed; but it would be a long and arduous task even for the Al Abassi to make an artform of magic that could rival the spells cast by the people of Yevon; who had had more than a milleniums worth of training, practise and refinement in their craft. Green Mages simply were not powerful enough to contend with the far more offensively inclined black magi and their superiour magical systems. In raw force, they always lost, because the restrictions on their craft prevented them from harnessing more energy than they could safely handle, whereas the black magi had already discovered ways to circumvent the disadvantage of spellburn by making use of either implements or the much more commonly used Entite Solution.
Something had to be done, so therefore - the Al Abassi gathered all of their tribe chiefs and asked them to trace the leylines of the world where they travelled and connect them to the art itself by means of a secret formula and some alchemical solutions. In return the tribe who invented Green Magic would share all their knowledge with their fellow clans. The Al Abassi are nomadic by nature, so there was little problem with carrying on with the task, as they would scatter to all winds and trace leylines in all the remote corners of the world where they temporarily settled down. In the span of a century the Al Abassi had, in their constant journeys managed to trace most of the leylines that existed in the world - and these concentrations of aether, present in the earth and environment were now connected to the artform itself.
The magical powers of the Green Magi had risen steadily over this century and where they might once struggle to manipulate something or conjure even a single gust of wind, they had now become capable of meeting other magi such as the black mages of the humans in direct combat. Although they still found that it was difficult for them to fight against those mages who had grown accustomed to the use of Entites, as those would often overwhelm them with powerful multi-directional attacks. This lead to another ability of Green Mages, for soon they too came to understand just what these magical constructs were composed of; and, in their quest to protect themselves and their people - they gradually learned how to tap energy from these entites much like they would tap energy from the world itself, a talent which fuelled their ability to defend against the destructive arts.
Green Magic is considered to be more complicated than most other forms of Spiran Magic, this is because its more encompassing than simply drawing upon aether and forming it into the desired shape the way Black Magi do, only possessing a single line of conjuration spells. The reason is, that the foundation of green magic is built upon harnessing the powers that be in the form of a way known as "channeling" to produce the desired effects. This is usually accomplished by the innate ability of Green Magi to affect and manipulate a locations latent elemental and magical power to their own uses. Green Magic spells are among the most versatile among the disciplines of magic, being capable of protection, healing, offense, restriction and inducing weakness. Green Mages are capable of using all elements depending on their access to elemental sources, but generally use spells which deals with earth, plantlife or air.
A System of magic is a term that denotes a certain way of practising, harnessing and directing magical power which, due to the particularities of each system almost invariably ends up being very different when compared to another system. With those untrained in the arts often misunderstanding two mages whom practise different systems of the same magical disciplines to be practising completely different magical arts altogether.