An ancient secret Romulan order devoted to preventing the creation of synthetic life, revealed in Star Trek: Picard.
The Zhat Vash is a centuries-old Romulan order whose members fear artificial life after learning of a warning, known as the Admonition, left by an ancient civilisation. They operate in deep secrecy, even within the Tal Shiar, and work to suppress synthetic beings wherever they appear.
In Picard, Commodore Oh of Starfleet Security and the agent Narek serve the Zhat Vash as they hunt Soji, a synthetic descendant of Data. The group was behind the synth attack on Mars in 2385 that led the Federation to ban synthetic life.