Dungeon World System
Magic is Far more complex in reality than players would ever know. The idea here is that Any mage can create a spell, provided they know
A) What they want to achieve
B) Have a clear understanding of how magic works
C) have the time to make it work.
Now that its settled.. Magic in its understanding is very limited.
Many different groups of Magicians have developed many different spells over many years, some of them have come together to create magic schools, develop their Magecraft and become great and powerful magicians. the only real problem with this method is, alot of time and effort goes into finding magi, training them in many aspects that they may or may not be proficient in, only to create an average mage, while more concentrated 1:1 training from a magi to an apprentice, is that the apprentice learns all the mage knows and is ready to take that knowledge one step further as soon as his training is done.
Magic is known at the moment by many magi to flow through Elements, There is alot of debate about this, Some feel that the Elements are 3, Magenta, Cyan and Gold. Other Scholars of Magic feel that there are 4.. Magic-Fire, Magic-Water, Magic-Air and Magic-Earth. While another school of thought is 5, Magic-Fire, Magic-Wood, Magic-Steel, Magic-Water and Magic-Air.
The problem with Each of these views, is that while alot of Magic flows through the Elements, there are other small aspects of magic which do not.. leading to the rise that possibly other magics exist. Some state that 7 exists (one for each colour) others 10, 12, 16 or 20.
For example.. While its recognised that magics exists in Elemental forms, there also seems to be groups, such as Magic-illusion, Magic-battle magic, Magic-nature, Magic-summoning, Magic-alchemy, Magic-prestidigitation and even a raw form… which magi involved in magic battles frequently witness.
Then there are the other schools of thought. Sorcerers believe that magic is a form of energy and it bends to the will of the user. If the user thinks that it will flow like water, it will do so because that is how it is believed.
The Thaumaturgists, Do not use magic (traditionally) their power comes from the mind, but some Magi feel this is just another school which has yet to be understood.
Priests ask the gods about this, and get no real clear answer.. because the gods don’t want priests to split their allegiance. (there is no god of magic .. yet)
Interestingly but not surprisingly.. no one is right. (Even I, the creator, cannot say what the truth is.. as no-one has gone far enough to push the bounds of my knowledge to create what it is.. but I have a fair idea)
For Now.. You can Understand that there are a few schools, they will teach you a set of spells that they have managed to understand the techniques how to cast and how to become good at casting those spells. but beyond that.. magic can do ANYTHING.