Alijuran clan
Curses are when someone uses their magic to change the future to their liking. Changing the future is extremely difficult, often there are too many factors working against a curse that even with manipulating the untainted future will happen. But simple things such as personal decisions, momentary decisions or the actions of one individual have so little opposing factors that they can be manipulated. This is where the Clan finds the greatest success.
The more unlikely the curse the more energy the castor needs to put into the threat. If the castor wants their opponent to do something improbable they need to produce enough energy to physically change the moment's circumstances, and put in even more effort to keep those circumstances manipulated.