Antediluvian

The Antediluvians are the precursors to the vampire clans in Vampire: The Masquerade.

According to Noddist lore, Caine sired three childer, who in turn collectively sired thirteen more. Caine left the First City, leaving his childer unattended, and the thirteen slew them, prompting Caine to lay curses upon each of them. When God attempted to cleanse the world with the Great Flood, the thirteen managed to survive and sire new childer, founding the Kindred Clans. Those thirteen are considered the Antediluvians, from the Latin phrase "Before the Flood."

Although the canon of the Book of Nod identifies thirteen distinct Antediluvians, other sources have other claims. The Erciyes Fragments identify six childer of Caine. Vlad Tepes came across four different counts in his research, including zero. Ravnos lore has the gods create Zapathasura. A Setite legend has Set become a vampire on his own and the gods created the other twelve to oppose him.

In the modern nights, the Camarilla denies that the Antediluvians still exist, claiming that they must have been destroyed in one way or another long ago, while the Sabbat seeks to consume their power. Either way, everyone agrees that an Antediluvian walking about openly is an Extremely Bad Sign (except for some vampires that want just their ancestors to return), and more than one active Antediluvian is probably the sign of the Apocalypse. Millennia of paranoia with godlike powers makes these figures worse than Caine himself, since there's a good chance Caine might consider the PCs to be beneath his notice.

Antediluvians serve the same purpose as the "precursor" trope in sci-fi settings, with a healthy dose of "ancient evil" on the side.