Curse Magic

Curse magic (also known as the Art of the Furious Mask) is part of what is known as hedge magic or common magic- magic embedded in worldwide folklore that is accessible across class and cultural lines. Curse magic is perhaps the most taboo of the magical arts, and is rejected in most cultures as both peasant-magic and evil magic. It is the craft of "witches" and "crones", and the basis for persecuting the sick, the foreign, and the weak during times of crisis. Accused curse-casters are the universal scapegoats, for many fear their arts.
Curse magic requires some knowledge- more than Tragedy Magic but less than Comedy Magic - and foci to concentrate one's hatred towards the target. It operates on the "Rule of Three"- that however you curse the target, you will be struck down three times as hard. As such, it is the weapon of the desperate and the hateful, those with nothing to lose or those who gain more by causing harm than they could ever lose. 
Mechanically, Curse Magic follows these rules:

Requires components, and charges via time

- Requires a focus relating to the target (icon, something from them)

Effects: if the target fails a Will save (DC: 8 + proficiency bonus + Wisdom)

•  Bodily Harm: most dangerous form, target gets a Will save; 1d6 per hour
•  Misfortune: much more ambiguous, DM's discretion
•  Fatigue: 1 level of exhaustion per 3 hours of focus

Will immediately strike the user with 3 times the damage, fatigue, or misfortune as dealt

Cultural Attitude

• Desmia  considers Curse Magic an art exclusively for priests and those chosen by priests to be Curse-Martyrs (those who volunteer to suffer to harry the foe, often the old or ill who cannot otherwise help protect their community). To use Curse Magic without temple permission is to violate religious law
• Sonev persecutes curse-magic relentlessly, torching entire communities who would harbor such a witch. 
• Suneka sees Curse-Magic as inherently discordant and disruptive, and any evidence of curse-magic will quickly see one sent to a monastery of the Goddess Nukima for re-education. There, the masked priests use an elaborate system of torment and discipline to disorient their subjects and prevent them from successfully casting curses. Some curse-makers eventually graduate and even re-integrate into society; most are stuck doing forced labor for the rest of their lives, or kept on probation in a cycle of re-incarceration.
• Samvara, Inahng, and most of Garadel  considers curse-making dreadful witchcraft that must be persecuted and destroyed. The Zesheko religion considers curse-making a dangerous art that must be reserved for priests and warriors.
• Maradia and Ekraht both blame and persecute curse-makers for plague, famine, and most misfortune, but sustain a healthy population of curse-makers anyways. This is not intentional- in both lands, it is more a product of elites keeping captured curse-makers as personal weapons against their rivals than any kind of intentional policy. Nonetheless, the custom has led to the desperate learning curse-casting in hopes of finding a better life with a wealthy patron- generating a cycle of paranoia and hurt. 
• Nafena captures and magically mind controls all curse-makers for collection into the Dread Choirs: great groups of curse-casters who are used to target enemies from afar. Not all of the Dread Choirs are mind-controlled; some are raised for this, as martyrs in times of need. While technically secret, all know of these Dread Choirs, and fear their wrath.
• Ibith has a custom where curse-making belongs in the hands of priests and healers- only those who have mastered the light can wield the dark. All others are seen as ensnared by dark spirits and doomed to a tragic end.