Curses (呪法, Jūhō) are the main form of combat commonly utilized by False Demons.
Curses are naturally imbued within the physiology of every demon; unlike magicians, who are known to be rather rare in Earth Land—this, along with enhanced physical powers, is what puts demons ahead of humans in terms of combat prowess. Whilst similar to Magic in several regards, Curses are more foul in nature and are superior in the regard that they, and those who utilize them, are unaffected by Magic-canceling/nullifying objects, such as Magical Barrier Particles and Face. Also, like Magic, Curses come in a wide variety, such as Jackal's Curse involving explosions, Tempesta's involving paralysis, and Sayla's involving body manipulation. Curses are not to be confused with Magic, wherein the kind that they use are considered to be of the highest tier. The demons that Zeref has made have a biology similar to humans and beasts in that they use standard magic, and don't have Magical Barrier Particles; because they are quite literally darkness incarnate. However, on the other hand, the ones made by Magical Barrier Particles; their biology revolves around those, and hence they can wield "Curses". While they are called Curses, they are simply the replication of effects conjured by Eternano through Magical Barrier Particles, hence causing magic to be relatively ineffective against them. E.N.D seems to be one of the few true demons left, and it is widely speculated that he created the demons of Tartarus; who in turn turned out to be artificial demons, allowing them to wield curses. Therefore, it is assumed generally that Etherious retain the ability to use proper magic - in this case Black Arts - and the artificial demons wield curses.
Curses are not to be confused with Magic, since Magic is fueled by ethernano particles, and Curses are fueled by magical barrier particles, which are otherwise known as anti-magic particles.