Perhaps, we should start with the possible victims, that is, those for whom the magic can be dangerous. Incorrectly create a magical design, even conceived as a safe and even harmless, because rendering is becoming risky, just one mistake and dangerous magic in front of you. It can become a victim of the magician himself. Did not calculate the margin of the internal energy, time has not made up for it, and by the victims. For the same reason, can suffer and the object for which all was started, or even a stranger, so to speak, a party that has nothing to do with magic, and the fact that the magician going to do. Dangerous magic become such when there is inattention or overestimation of its own forces. However, this does not happen often, learning, and even more so, magical practices, starting with the basic rules of safety.
Further, the risk may be so-called rebound. That is, the situation where the magic design was created correctly, truly focused on the object properly interact with it, but the energy was excessive, there was a stir, and some of the energy went into the side. When rebounding, often suffer outsiders, the third party was in the wrong place at the wrong time. However, under all of the same safety with timely reaction rebound can be avoided - for example, using the formula, "just in case" prepared in advance magician.
But still, it is exposed to the greatest risk magician. The reasons for this, there are many, the most serious of them, the development of new magic formulas using the energy of the space, there is always the risk of detonation energy flow when a certain channel has more than enough energy and that energy has different purity fluctuations within a single thread. Of course, the risk to which the magician is, consciously, because at certain times of risk, scientists, master the radioactive elements.
There is also a danger to cause effect, the absolute control of which is impossible. Typically, this is the ancient demons of the elements, known for their power, and generally bad character. Faced with such a creature, the magician is forced to engage in a real fight, the outcome is unpredictable.
However, some risk exists even when using household magic. For example, if you create a love spell you can come across a magical structure of the opposite direction, the result of such an impact, of course, less deplorable than after the fight with the demon, but I still need some time to recover the magician.