Mirren Hadar was a Cardassian civilian engineer stationed at a Ketracel white manufacturing plant. He used his position to provide the technology involved in synthesizing ketracel white to agents of the Romulan Star Empire's Tal Shiar. Hadar would also assist mercenaries hired by the Tal Shiar to raid Starfleet ships for the latest technological innovations in order to assess which side in the Dominion War was a bigger threat to Romulan interests.