"Well done, Commander."
Eris was a Vorta agent in service of the Dominion. She was involved in an attempt to infiltrate the Federation in late 2370. She was the only Vorta known to apparently possess telekinetic abilities. She claimed she was from Kurill Prime.
While Benjamin Sisko and Quark were on a camping trip in the Gamma Quadrant with Jake Sisko and Nog, Eris appeared at the campsite posing as a refugee from the Dominion. She claimed she was a Kurillian who was on a freighter heading home when their homeworld was conquered by the Dominion. The freighter fled from the Dominion; however, the Dominion pursued the ship as it was carrying Eris. Eris' mother was an outspoken opponent of the Dominion, and, in the opinion of Eris, the Dominion wanted to make an example of the family by the capture of a family member. The three of them were then captured by the Jem'Hadar, allowing Eris to gain Sisko's trust. Eris was apparently fitted with a telekinetic suppression collar, and she helped them escape after Quark unlocked the device.
However, Quark later discovered that the collar was nothing more than a complex locking mechanism, while attempting to strip it and sell the plans for profit, and that Eris could have helped them at any time. Her true mission exposed, Eris escaped from Deep Space 9 via a transporter. (DS9: "The Jem'Hadar")
Background information Edit
Eris was played by Molly Hagan.
Hagan commented on her excitement at playing the character: "Number one, seeing that I was the first Vorta, the first of a new kind of previously undiscovered humanoid. Number two, seeing that I had telekinetic powers. Number three, finding out that I was in fact the bad guy. I just couldn’t wait. I immediately began working on a physical gesture that would indicate when I was using my telekinesis. I thought it could become the defining gesture of my people, like the Vulcan "Live Long and proper” hand gesture. So, I came up with a motion where both my hands looked like they were taking energy in from my body before I pulsed it back out through my hands. It reminded me of something I saw Bruce Lee do. It never got used because a) they had great special effects and didn’t need me to do any gestures to sell “my powers" and b) they were concerned that any future Vorta may not be able to replicate it. I was beyond disappointed." 
Hagan was helped to adjust to the prosthetic makeup by Armin Shimerman. Hagan commented: ""I adored Armin. He was so kind, talented and patient. He was in the makeup chair before I was. He taught me what to expect with wearing prosthetics and because he was so patient I learned very quickly that I should be patient, too, even though it only took a third of the time to apply my ear pieces. I got to talk with Armin while we sat in the makeup trailer and it was a real treat and an honor. My memories actually have a lot to do with makeup and hair because I had to come to work around 4 a.m. The shooting hours were also long, so by the end of the episode my internal clock was messed up. For about a week after the gig had wrapped, I still didn't understand what time of the day it was and I lost a big chunk of hair. I gained tremendous respect for the cast of this show and other Star Trek series because I finally understood what kind of hours and dedication it took to film these" 
On the Vorta makeup itself, Hagan commented: "It was a thrill to get to meet Mike Westmore, let alone have something designed by him on my face. I was so excited to have my face cast done in the workshop where they imagined and created all the appliances. I loved my wig, loved the prosthetics and loved the beauty makeup they put on over it all. I thought I was so pretty. And the contacts! I loved the contacts. It made me instantly feel “other.” That is the beauty behind getting an opportunity to wear a Mike Westmore design. The outside helps the actor create an internal experience that they would not otherwise have. It makes the acting better. 
Hagan commented: "Well, I took a gamble and I lost, on both counts. I was not available because I was testing for an NBC pilot with Dabney Coleman called Madman of the People. Needless to say, I didn’t get that role, and by then DS9 had moved on and retooled the character, so Dennis Christopher took over as Borath. I was deeply, deeply disappointed. But it was my fault". 
In the novelization of "The Search", it is Eris and not Borath who is running the mental simulation from "The Search, Part II". In "The Search, Part II", Sisko asked Borath, "And you're one of the founders?" to which Borath replies, "that is correct. You seem surprised." Sisko implies that he did not ever formerly suspect that Eris was one of the Founders. However in a prior episode ("The Jem'Hadar") he asks Eris, "you're one of the founders, aren't you?" As such Sisko is hiding from Borath some of his former insight.