Unidentified Mind Reader Sisters

Twin sisters who had the ability to read minds were ordered by Holland Manners to find out who had betrayed Wolfram And Hart to Angel after Lindsey McDonald betrayed them in order to save the Holy Triumvate from the assassin Vanessa Brewer. The twins not only discovered Lindsey's betrayal, but also discovered that Lee Mercer had been in secret talks with Wolfram & Hart's rival law firm, Klein & Gabler. Holland had Lee killed by Phil for this, but had a soft spot for Lindsey and decided to let him live, even when Lindsey continued to assist Angel and resuced the Holy Triumvate, getting Vanessa killed by Angel in the process.

It was later confirmed by the doomed-to-die Winifred Burkle that everyone at Wolfram & Hart apart from Lindsey and Liliah Morgan had been killed by either the Beast or Darla and Drusilla, (the Beast was later killed by Angelus and Darla commited suicide, Drusilla remains at large) so presumably, the twins died since the events of Blind Date, at the hands of either Drusilla, Darla or the Beast. Lindsey, meanwhile was later killed by Lorne, while Liliah was killed by a Jasmine-possesed Cordelia Chase (Jasmine was killed by Connor, while Cordelia slipped into a coma as a result of Jasmine's possession and died).

Though the twins were apparantly human, they had the ability to read minds, which is an ability no human on the show-with the exception of Buffy in one episode after absorbing some demon blood-has ever been able to do, so they were presumably part-demon.