For the Magic with a similar name, see Curse Magic.
According to Mard Geer, hundreds of years ago, The One Magic developed into many different kinds of Magic, however during that period of development and expansion, E.N.D. discovered a different route that Magic could take and thus created Curses. With its power rooted in the negative emotions set forth by humans (such as greed, envy and hatred), many Demons that utilize Curses call it the ultimate power, most notably Mard Geer, who goes as far as to say that Magic has no future and that Curses are the superior ability that rule over all others.
Whilst similar to Magic in several regards, Curses are more foul in nature (a notion supported by the fact that Curses are run off of negative emotions) and are superior in the regard that they, and those who utilize them, are unaffected by Magic-canceling/nullifying objects, such as Face. Also, like Magic, Curses come in a wide variety, such as Jackal's Curse involving explosions, Tempester's revolving around natural disasters, Franmalth's involving absorption and application of his absorbed material, Kyôka's involving altering physical sensitivity and empowerment, Ezel's involving the usage of arms as a blades, and Seilah's involving command and control.
According to Jackal, Curses are not to be confused with Magic and are used by those at Tartaros, wherein the kind that they use are considered to be of the highest tier. Curses are accordingly run off of Curse Power (呪力 Juryoku), which in and of itself is the manifestation of powerful, negative human emotions.