On Janoch all magic users must have a bond mate. In some cultures they are bonded from birth, in other when their magic begins to show, and occasionally at some point when their culture decides they are an adult, but if a magic user doesn't have a bond mate then there are problems. Magic here, unless used in the way it is meant to be, can overwhelm a magic user, which leads to the death of the user, as well as people around them. There are warning signs, so something can be done to stop it, but there have been times when there haven't been enough magic users to bond them all together or other problems.
In all there are six races of magic user on Janoch and each has different abilities, although they all suffer from the same problem. This wasn't what was planned for this planet, but it was the way magic evolved on this world, so the races here simply had to get used to what had happened to them.