The Black Market that can be found in every Kingdom generally serves for the trafficking of Cures.
Curses range from simple changers (physical transformation) to highly complex harbinger curses (death, ruination, terrible luck).
While harbinger curses are used for revenge or some other reason to bring these things onto a hapless person, minor curses are often used cosmetically.
The Nobility of certain kingdoms is known for using changers to give themselves unique looks, usually depending on the culture. Scales in Zalcoatl, bat-like features in Kamazoalt, blue or red skin in Orus.
The Seraphim have a natural resilience to curses, those afflicting them rarely have the desired effect.