This sounds really good. Have you worked out any specific details? Like how this magic thing will work? Is it elemental? (fire magic, water magic, etc.) Can you create something out of nothing or do you have to use something around you that already is there? (bending)
Well, what I have in mind is that there will be a number of Schools (in lack of better word) of magic, and that these are in a sense different ways of viewing, and utilizing, the raw and chaotic power of magic. In a sense the mage has to vizualise magic from a specific point of view before they can use it, as if through a lense.
Then there's the level of commitment into one, or several, School(s) that determines what a mage can and cannot do. The more focused one is the more ways can they manipulate their school and the more impressive effects can they achieve. A mage with very high levels of mastery in one school will be able to generate their spells seemingly out of nothing where a less experienced one may need a vast array of foci, symbols and reagents to help their concentration.
Of course, there are costs associated with spellcasting. Both in the sense of expendable resources, like reagents or the physical strength of the mage to name two, but also the very direct effect which magic has on the mage themself. With no exception any mage who reaches a certain threshold of control over magic will also unavoidably be changed and partly controlled by it. Essentially a more focused mage will ultimately become physically and mentally altered to accomodate their increased focus into one school.
What does this mean mechanically?
Well, it means that a mage will have one primary School, into which they've put most of their devotion and discipline, and a number of secondary ones. These make up the very basis of their spellcasting. They'll also have a number of points to allocate among these to give a rank ranging from 1 to 10, where 1 represent the most basic of knowledge and 10 is exceptional prowess.
Now, I'm not going to go into specific details of what a mage with ,say, 10 in fire can do compared to one with 5, rather I'm going to say that they both -can- do pretty much the same feats, but that the mage with 5 in Fire will need significantly more preparation, symbols, reagents, foci and what-have-you to succeed. Ultimately it'll be down to GM fiat if one spell succeeds or not.
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On the world:
The game will take place in a reasonably low fantasy medieval setting, which is populated by more or less only humans and fantasy creatures will be for the most part be the stuff of legends. They exists of course, and a lot of people will suspect or even know that they do, but most of the populace will haev never seen one.
One of the things that people
do know exist are the mages of course. They're there, they have a place in society; serving the lords and kings and other powerful entities and organisations. That is to say, those few mages that so far have not been deemed dangerous have a place in society, and they are constantly watched by an organisation called Disciples of Odna, an order of knights, priests and inquisitors who have as their charge to protect society from rogue magi (and creatures).
There's no trial for a mage caught by the Disciples. Be it due to the whims of an influencial noble or because they actually pose a threat to people it's seldomly something which matters when in the hands of these men and women, and a mage is as a rule either executed on the spot, or sent of to the prison.
As for society as a whole, and on a more local level:
Locally a city, town or fiefdom will be ruled by a noble, usually a Count or Baron but sometimes also a Duke. Powerful and wealthy they are only subject to one person; the King, and even then many of them are largely independent. Not only that but they also form up a noble's council twice annually who together have the power to influence the King's decisions.
Below the nobles is the church and its Disciples of Odna, but not far below as in some cities they are more influencial than the nobles, and it's been known that knights of the Disciples have been granted noble titles themselves. Officially however they are below the nobility, and answer to their whims and the whims of the King.
Then we have the guilds, merchants and other wealthy individuals who, thanks to their wealth and importance in running the cities, have a great deal of influence at least on a local level in their settlements. Men-at-arms that aren't militia are generally counted into this group as well.
Craftsmen, traders and jsut about anyone else who lives in a city come next; Burghers as they are called. They are many, being the second largest group of people in the nations, though despite this have very little say in the ruling of their home cities. Instead they generally have to contend with what their betters decide.
Further down the ladder is the peasantry. Farmers and heavy manual labour almost exclusively. They make the workhorse of the nations, and is by far the largest group as well. They have practically no say whatsoever beyond the People Councils that form they form together with the burghers bi-annually or so, and even then their role is strictly advisory at best.
The group below them conists of the unwanted and despised; beggars, criminals, traitors and, of course, rogue magi among others.