Well, I'm glad to see that I'm getting a lot of interest. ^_^ I think I can go ahead and create the OOC thread today. However, before I do that, I want to make something clear. Since there is only one spot available for each type of magic user, this will be on a FIRST COME FIRST SERVE basis. Therefore, if you've called "dibs" on something, you'll have to be the first one to create a character and have it accepted. Once I accept a character, I'll write the person's name next to the type of magic user to show that the position has been filled, and then that character will be the only one of that type of magic user. I don't mean to create conflict, but I figure if you really want the spot, you'll be quick to crank out a character. On that note, I may accept a character before suggesting minor tweaks, so the sooner you actually complete the character and submit it, the more likely you are to gain the role you desire. 

Now, to answer some other questions. This will be a fantasy world, but one without magical creatures living in that world. Magic exists, but any magical creatures that are present in this world will have to be summoned or conjured from other planes or worlds. The setting is likely a small medieval kingdom. Magic users in this world are rare, about as common as albino animals in the wild. However, magic is hereditary, meaning that the offspring of two magic users has a good chance of being a magic user himself. No one is ever born with mixed powers, they are either inherently one sort of magic user or inherently the other. How magic users are seen is largely dependent on the type of magic user they are. Warlocks, Sorcerers, and all four types of Mage are generally seen as powerful, and are respected, but to be avoided unless necessary. Wizards and Enchanters are highly respected and often even held in awe, though they are also treated with much caution. They are often employed by royalty, or are solitary and reclusive. Seers are the most easily accepted of the magic users, generally accepted by all for their knowledge, though they can sometimes create enemies when the subject of their predictions doesn't like what they hear. Summoners are highly distrusted and even shunned, as most folks believe them to have sold their souls to devils in exchange for their powers. This is not usually the case, but the stereotype is kingdom wide. Necromancers are outright hated, their arts illegal throughout the kingdom. Known necromancers are hunted down and slain, though every once in a while a lord or other noble may employ them secretly. Druids are generally misunderstood and mysterious, no one really knows much about them and they are treated with a mix of curiosity and superstition. They generally aren't treated poorly, though they may be avoided simply because of their odd appearance.

Humans are the only playable race, yes. Two magic users may combine effects, yes, but they must train together quite extensively to gain enough familiarity with one another and the magic of the other to produce viable outcomes. If two strangers tried to combine magics without knowing the styles of the other, the results could be disastrous. These kinds of alliances are rare, however, as most magic users consider themselves as having the best sort and are reluctant to put the time and effort into tracking down a magic user of the desired type in order to work with them and their "lesser" magic. 

There have been requests for a few more details, so I will give details on the rest of them here.

Wizard- These magic users have the broadest range of effects they can produce, as their power comes from arcane knowledge and lore. The effects they can produce vary greatly. It is easier to simply state that they can possibly duplicate many of the effects of other types of magics, with certain exceptions, and never to the degree of the actual type. For example, a wizard may be able to create a fireball or a flaming wall, but they cannot wield fire like a fire mage does. These are the types of magic that cannot be duplicated by a wizard. Necromancy, Enchanting objects, Divination, Summoning, Druidry. Also, Wizards and Sorcerers are the only magic users that can wield lightning.

Sorcerer- A sorcerer draws his power from his own inner life force and willpower. He can copy the effects of Mages to the letter, as well as wielding lightning, and can also use raw invisible force to various effects. However, unlike a wizard or a mage, his capacity for casting magic is limited. Since the power comes from his own life force and will, he can only sustain the effects for a certain amount of time and can only cast so many spells in a short amount of time before he begins to physically wear himself out. It is possible for a sorcerer to kill themselves by using too much energy, though most of the time they would simply pass out before that happened. After resting an amount of time equal to the energy spent, he recovers his energy. However, passing out does not count as resting.

Fire Mage- A fire mage is able to both produce and control all manner of fire and heat, though he cannot wield lightning. When producing fire from himself, it takes an amount of energy equal to the amount produced, similar to a sorcerer. When controlling existing flame, he expends no energy. The limits of what he can do with the flame are only as limited as his imagination, though he cannot create living fire beings.

Water Mage- A water mage is able to both produce and control all manner of water and cold, even including ice. When producing water from himself, it takes an amount of energy equal to the amount produced, similar to a sorcerer. When controlling existing water, he expends no energy. The limits of what he can do with the water are only as limited as his imagination, though he cannot create living water beings.

Earth Mage- An earth mage is able to control all manner of earth and stone, but not metal. He cannot produce earth or stone. The limits of what he can do with the earth or stone are only as limited as his imagination, though he cannot create living earth or stone beings. Most non metallic minerals count as stones. For example, jewels and gems count as stone and can be manipulated by the earth mage.

Air Mage- An air mage is able to control all manner of air and sound. He cannot produce air, but he can produce sound. The limits of what he can do with the air or sound are only as limited as his imagination, though he cannot create living air or sound beings. An air mage can control wind, but cannot create weather patterns. For example, he could create a tornado by whipping the air around quickly, but it would have to be sustained by his power, since he cannot control clouds.