Black Sun is a reference to a solar eclipse, better known in the context of the Curse of the Black Sun, or the Mania of Mad Eltibald.
It was prophesied by the mage Eltibald that an eclipse foretold the end of the human civilization in the hands of sixty girls born during the Black Sun, which would turn them into cruel creatures, who would bring about the return of the goddess Lilit and the end of the world.
Eltibald wasn't mad at all. He deciphered the writing on Dauk menhirs, on tombstones in the Wozgor necropolises, and examined the legends and traditions of weretots. All of them spoke of the eclipse in no uncertain terms. The Black Sun was to announce the imminent return of Lilit, still honoured in the east under the name of Niya, and the extermination of the human race. Lilit's path was to be prepared by "sixty women wearing gold crowns, who would fill the river valleys with blood".
First wizards such as Stregobor, hunted down the girls, killed them and performed autopsies when possible. After a while, when they admitted that recognizing the girls was hard, they opted to simply lock them up into towers, to isolate them. That plan suffered, because there was a brief fancy of saving beautiful girls from towers among princes. One after the other, though, the girls either perished or managed to flee their towers, and grew mighty enough for the wizards to leave them alone or get them in other ways.
It might be that the Curse became a self-fulfilling prophecy, for some of the girls who managed to flee the persecution later inflicted cruelty on others because of the treatment they had suffered.
Girls said to be afflicted
The Price of Neutrality premium module
In this premium module for The Witcher, Deidre is Eskel's surprise child, born under the Black Sun and prophesied to ruin the world and the sister of the nobleman who wants to make sure she will not have the crown. Sabrina wants to kill her as well to examine her body and discover the truth about the Black Sun - being The Witcher, Geralt has to choose with whom he sides.
- Eltibald's prophecy had wide repercussions –- to this day the debate rages as to whether it proved true or the ravings of a madman. In all certainty, there occurred a solar eclipse after which many mutated girls were born. Some of them were isolated from society immediately, from whence the tales of princesses imprisoned in towers atop glass mountains and princes who set out to rescue them.
- Rumors abound regarding bloody female outcasts born under the black sun and resembling women only in appearance. Many say the creatures proved nothing more than cruel monsters. Mages agreed to explore the matter and proceeded to employ various means in the investigations. Vivisections proved necessary in some cases, proving the only certain way of revealing the evil mutations. However, they could not agree on whether the internal anatomical deformations they discovered were decisive of the creatures' evil nature.
- The Curse of the Black Sun was prophesied by the mage Eltibald, who predicted the return of Lilith, a mythical being who is to bring ruin upon the world. Lilith's second coming will be preceded by the appearance of "sixty maidens wearing gold crowns, who will fill the river valleys with blood," thus preparing the way.