Rule One: Magic is physically corrupting
The mortal shell is ill-suited to casting arcane magic. Arcanite grows within the spellcaster’s body. As he develops magic, he also develops health complications from these quartz-like growths that press against the body’s vital organs. Wizards live a life in fast forward; they gain extraordinary amounts of power quickly, but soon die in a few decades from their cancerous curse. Sorcerers have mutations in the blood that allow them to adapt, though they aren’t as ultimately potent. The lesser arcane spellcasters experience these symptoms to lesser extremes.
Rule Two: Magic is mentally corrupting
Neither nor Wizard, nor Sorcerer is immune to the semi-addictive nature of magic – Wizard’s are particularly susceptible to the lure of siphoning. Arcane power, like any power, corrupts. And all too frequently, a mage’s wisdom gets outpaced by their gains in power. The college of Alexandria takes great pains to ensure its students are endowed with a sense of responsibility over their powers.
Rule Three: Magic attracts the Astral Existence
Alien creatures can enter the Material World with the aid of Arcane Magic. Worse can enter in the presence of the infamously tempting, powerful, and corrupting Eldritch Magic.