Cursecraft is a type of Magic inherent and exclusive to the Kalar race. All the members of the race have this ability, even if it's Lv0. Typically, the most basic curse a kalar posseses is that to kill the one that pulled the crystal out of their foreheads. It is the final vengeance of the Kalar to its killer.
Those with more advanced skill levels in cursecraft can deliver different curses to humans, and not necessarily lethal. Curses have a wide variety of effects, which depend on the kalar that created it.
The Kalar Queen usually has the most powerful level of spellcraft. One of the most feared abilities of the Kalar, is the Curse of the Queen, which instantly kills all male humans that are in Kalar territory.