She was played by Molly Conarro.
Eloise Sanchez did a stint in a juvenile psych ward before the events of the episode, as she worshiped Haitian goddess Erzulie and was aroused by watching things die. After being released, Eloise engaged in a relationship with bartender Kai Bryant, and the couple would kidnap girls and kill them, feeding into Eloise's twisted desire. Kai would find the girls and take them to their home, where Eloise would prepare them to be killed.
Eloise and Kai had killed a young woman named Laura Anderson, and they did the same to Windi Stewart, who was the girlfriend of Cade Lambert, Chris LaSalle's brother. Windi's body was left in the trunk of Cade's car, and Kai drugged Cade to frame him for the murder.
Eloise's necklace was left on Windi's body as part of their routine, and when Brody met Eloise (who posed as a witness to Laura's murder), she saw a tattoo on Eloise's back that matched the necklace's design. It was at that moment that Kai popped up with a shotgun pointed at Brody, which revealed Eloise's true role. The psychotic villainess tied up Brody's hands behind her back, but Brody quickly broke free of her capture and fought the couple. After Brody killed Kai, Eloise went after Brody with a gun of her own, only to be shot dead by Brody.