Restrictions on Magic

Hello all! It's been awhile since I've been active. The Navy decided to pull me away with training, but now I'm back for awhile. :^)

Anywho, I've been working on constructing a magic system. I really like the basis I have for it, but I'm having difficulty restricting how magic is used in the world. I don't like vague things when it comes to my world's fundamental physical laws, and I want to at least get a common rule set on what things can and cannot be done with magic. Here is the basis I have for magic in the world thus far:

Every human has a soul. The living body acts as a barrier between the soul and the afterlife. When a person dies, their soul moves on to the Eien, the Land of Eternity.

If a person loses all of their soul, their body also dies.

The Eien is the collective sum of humanity's spirit. When a person is born, a small portion of the Eien is extracted from the realm and placed in the human vessel.

As the person experiences a mortal life, their soul absorbs the information around them like a sponge as the mind interprets it.

As the person experiences emotion, their soul grows. Intense emotions can cause the soul to grow rapidly.
If a soul grows or shrinks too fast, it is possible that the soul will “fracture.” A fractured soul leaves the person able to use very little (if any) of their soul to channel their magic (the rest is still there, though it is cordoned off in a sense), and also leaves them with severe mental damage. Any event that causes them to remember the emotion they felt during the fracture could cause them to unintentionally release some amount of magic dependent on the size of the actual fracture.

When a person dies, their soul is sent back to the Eien larger than it was before (most cases), enhancing the power of the realm.

The soul may be used as a source of magic. Magic in this world is the projection of one's soul into the world around them. Projecting a soul usually requires a physical medium of some sort as a way to channel the power of their spirit so it is not a sudden release of energy. Most magi who attempt to use magic without a conduit end with disastrous results, such as using all of their soul at once or not being able to control the direction/formation of what soul they release. The vast majority of magi can only use one type of conduit (gemstone) in their channeling tool of choice. There are a very uncommon few that can use something other than a gemstone, and even fewer that barely require a conduit at all. Those few magi who can use any conduit they find are called Pure, because nothing about their soul is ever rejected. The Pure are usually the strongest of the magi, and at any given time only a handful of them exist across the world (even fewer realize their magical potential).

The strongest of the magi have found ways to tap directly into the Eien for limited amounts of time. These magi can perform extraordinary feats (making fireballs the size of houses, conjuring lightning storms, teleportation, flight). However, the massive toll on their body as being used as a filter prevents them from using any of these abilities for an extended period of time.

So, how do I decide what kind of magic a mage can cast, or how powerful they are without using some vague term like "years of endless training?"

 

The projection of all magic generates from the conduit and is oriented in a direction chosen by the user. Restricting the flow of magic in a certain direction is harder than letting it radiate from the conduit- therefore, many conduits come with a reflecting material of sort as to alleviate the burden of the user. The exact type of project is dependent on the user's mental state. Attempting to project spirit when the mind is not focused results in a dull hum of energy around the conduit that emits a small amount of light and heat. Generating an emotion and then focusing the mind around that allows for more powerful abilities to emerge- for example, a furious state of mind can project their soul into flames, while a soul focused on a chilling revenge may generate rays of cold that frost over their enemies. A powerful mage is one that has utter control over not only the emotions they are feeling, but also the intensity of the emotion as well.

Gemstones that have been used for long periods of time capture small pieces of soul due to their filtering capabilities. Over time, this can result in an amplification ability of the gemstone. Also, the use of soulgems in forging results in enchantment of the new item. (A small sect of artificers melts down soulgems and forge them together to make an extremely rare, volatile conduit known as a godstone).

Here's what I came up with after some brainstorming.

 

I appreciate the input, guys!

@Addison, I was moreso looking for a way to restrict the talents of magi in a logical way. What determines how much fire you can spew, or how much soul you can have? Just small limits that actually places a reasonable scale among the wizards of the world.