Almost 200 years ago, apocalypse came to New York City. The sky opened up in a ring of fire, and four demons came to set the world ablaze. A tribe of monster hunters, among them Brendan A. Allen, tried to stop them. But they couldn't do it alone. So the hunters joined forces with the monsters. Morgana, the sorceress. Dracula, the oldest vampire alive. Malec, the Dark One. Athena, a god on the run. Rumplestiltskin, a trickster who thrives on misery. Red Death, a Highborn autodidactic assassin. Turns out, even the most evil creatures in the world didn't want it to end. To them, Earth is home too. Together, they gave their blood and their sould to save the world. They performed a ritual to put the demons in the ground.

The Cabal acts as a seal, paying tribute to the ancient magic keeping the threat contained. Every year, the magic calls for a massacre, called the shift. The bigger the body count, the more effectively it holds the spell in place.

Most of the Cabal are men, not true immortals. Every 13 years, they undergo a treatment, a spell to keep them alive and protecting the city. The treatment involves slaughter of 13 children born on the day of the last treatment.