The historical accounts of the creation of the Kiasyd point to a trio of Lasombra who haphazardly delved into the roots of Obtenebration. The three vampires acquired through trade with a traveling wizard something labeled "the blood of Zeernebooch, god of the underworld". What was actually in the bottle no one knows for sure, but the three Lasombra assumed it was what the wizard said it was and they mixed it in with the blood of an Unseelie fae they had captured, and with some herbal essences and other less identifiable things. The Kiasyd themselves claim that Marconius was a mortal mage before the Embrace who specialized in alchemy and worked together with his sister Hrotsuitha to create a perfect being.
Records claim that during the reign of Roman Emperor Julian the Apostate (360-363 CE) a hapless Lasombra named Marconius drank the potion and rapidly changed: growing taller, thinner and even paler. His eyes changed to orbs of inky black, his skin became a glowing chalk white, and his features took on a pronounced fae appearance. The Kiasyd themselves claim that Hrotsuitha dabbled in Abyss Mysticism and that Marconius entered the Abyss itself and devoured his sister, changing himself in the process.
Needless to say other Lasombra noticed. The clan elders were displeased, not with Marconius, who probably was tricked into drinking the tainted blood, and not with the other two Lasombra who induced the changes in Marconius (they denied responsibility for their work, but Marconius identified them without hesitation). No, the elders were most livid at the whole situation. Unauthorized blood experimentation, trafficking with a mage (and not even learning his name?!), and possibly angering the fae community. Marconius was taken for trial before a Court of Blood and sentenced to banishment into an oubliette within Castel d'Ombro.
Marconius was freed by Gratiano after the Anarch Revolt, but the long banishment had taken its toll upon his sanity. His childer refer to his state as "Bedlam". Together with his brood, he took Strasbourg and drove off the Ventrue. The newly found Sabbat gave the rest of his progeny the choice of staying with Marconius or spreading thin. The Lasombra elders did nothing. The Kiasyd were only bothering the Ventrue and Strasbourg was hundreds of miles from any Lasombra stronghold.
As of the late 20th century, Marconius accepted an offer of the Camarilla and became the Prince of Strasbourg. In contrast to the violent reaction to a similar incident in Milan, most Sabbat did not react. Marconius had been seen as an eccentric at best and a liability at worst. His bloodline believes that his apparent defection is part of a plan.
The Kiasyd seem to hold no grudge over the ill treatment of their progenitor and Marconius himself has stated he is past the need for vengeance. The elders responsible for Marconius’ banishment are relieved at this, but the fact remains there are so few Kiasyd around they neither possess the strength or numbers to do anything about it.
A Dirty Secret? Edit
It should be noted that at the time of Marconius' transformation, the term Kiasyd referred to any faerie-blooded who had been successfully Embraced, and to the childer they sired. Around the beginning of the Renaissance, Marconius appears to have attempted to make himself and his childer the only Kiasyd, trying to eliminate all the others. The other Kiasyd gave him what he wanted rather than fight, giving up their name and territory and renaming themselves the Maeghar. As far as present-day Kindred society is concerned, Marconius and his line are indeed the only Kiasyd.