In late 2370, she took part in a Dominion plan to place a spy on Deep Space 9. She was encountered by Benjamin Sisko and Quark in the Gamma Quadrant and pretended to be fleeing the Jem'Hadar. She told Sisko that she was from Kurill Prime. After the group was rescued, she was brought to Deep Space 9. Quark discovered that a restraint on her neck could have been removed by her psionic powers. Her lie exposed, Eris fled the station, telling the crew:"You have no idea what's begun here." (DS9 episode: "The Jem'Hadar")
Eris worked with Borath monitoring the reactions of Benjamin Sisko, Jadzia Dax, Julian Bashir, Miles O'Brien, and T'Rul when they were placed in a mental simulation in early 2371. In it, Borath told Sisko that Eris was one of the Founders. When the simulation ended, Eris told Sisko that none of what he had experienced was real. (DS9 episode & novelization: The Search)
- While Kurill Prime was listed as the homeworld of the Vorta according to the Star Charts, it is not known if this is really Eris' homeworld or just a part of her cover.