Mages of the Gray
These spellcasters have given up their physical strength and the spirit of their being to pursue the path of infused spellcasting. They have twisted together the unique threads of both divine and arcane power, in turn creating new ways to power and knowledge. This fused magic bears both holy/unholy properties and the essence of might held by arcane magic. The spells created both heal and harm, create and destroy, seek and lose, they are entirely different than both branches they came from. These casters have also mastered a special technique that allows them to utilize special spell components to enhance the might of their spells.
In order to be allowed even a simple testing for the guild one must be capable of casting moderately powerful arcane and divine spells. If a potential member meets these requirements they are allowed to take a test which usually involves a short written exam about various magical topics and a test of skill. Usually the entrants have to face off against a large monster of some sort and protect a charge. This can mean stopping the creature from hurting the charge or healing the charge if the monster gets through. The guild spares no expense when deciding on a new member and will go to great lengths to prepare a challenging test for the testing pupil.
The Mages of the Gray are a unique bunch that have all sorts of unworldly powers, they have twisted together their own thread of magic that is completely their own. Besides wielding a different type of magic they are capable of casting many more spells than other mages due to the extremities they can force their bodies to. They can temporarily sacrifice strength and their own life force to cast more spells than they would regularly be able to. They are also avid users of power components which are special spell components that are potent arcane items much stronger than normal and can actually enhance the strength or duration of a spell.
Hundreds of years ago a great mage named Rathgor lived. He was a mighty spellcaster, expert in both arcane magic from his musty tomes and the divine magic granted by his deity. He sought a way to bind these powers together and create a kind of hybrid magic capable of titanic feats. He studied for nearly a century, for his half-elven life lasted that long, and came across a great grimoire of secrets. Scrawled in an abyssal tongue are the last words of a dark mage " to bind the magics sacrifice thy soul" and many formulas and codes written by the abyssal mage. Rathgor pored over the tomes rarely emerging from his chambers and only to take food or drink. Eventually he had deciphered the book well enough and he had learned the trick to the dark rituals and he thought he knew how to improve it. He gathered many strange ingredients, drew symbols of power everywhere and prayed to his god for guidance and then began the ritual ignoring the foreboding sense he was turning against everything that is natural and good. In a fortnight he emerged his body limp and haggard but his eyes lit up with a brightness that proved his victory. He had suceeded but with a price, his body had been ravaged by the extreme power of the magic. He had become very old in a short time so all called him Rathgor the Gray, he agreed but only because he thought that maybe arcane magic could be black and if divine magic is represented as white than his magic should be gray. He sought apprentices, and thus the order of the Gray Magi was born.