
Among those they turned into Chimeras were Theo Raeken, Belasko, Tracy Stewart, Donovan Donati, Lucas, Josh Diaz, Hayden Romero, Corey, Beth, and Noah Patrick. From then on, it was quickly revealed that they were experimenting on teenagers and turning them into hybrid creatures that became known as Chimeras, an artificially-created pseudo-supernatural being made up of parts of different creatures.

They first appeared in Creatures of the Night, when they were seen admonishing Belasko, a Werewolf-Garuda hybrid, for failing to kill Scott McCall and take his Alpha powers.

The Dread Doctors were the main antagonists of Season 5, though their influence on the supernatural world lingered throughout Season 6 as well. The Surgeon and Theo Raekenin The Beast of Beacon Hills
