The Breen were first mentioned in "The Loss", a fourth-season episode of ' which first aired in 1990. The episode established their race as one of several alien species to be unreadable by empaths, much like the Ferengi. References to them were made in several other "Next Generation" ("Hero Worship" S05 E11) and ' episodes but they were not seen until the 1996 "Deep Space Nine" episode "Indiscretion", which aired as part of that show's fourth season. They were depicted as running a mining facility from which Gul Dukat and Major Kira rescued Dukat's daughter, Tora Ziyal. According to "DS9" writer/producer Robert Hewitt Wolfe, after having previously been treated as red herrings since their first mention on "Next Generation", and as a running joke by the production staff because "they were these people who were out there who were dangerous but were never really responsible for any of the trouble going on", they would finally be used as the villains in an episode. Their true appearance would be concealed beneath masks, according to writer/producer Ira Steven Behr, because "I wasn't really in the mood to come up with a new alien race. So I said, 'Let's not see them. Let's just put them in costume because they normally live in the cold.'"