Tory Foster
From Wiki Frakr
Tory Foster, AKA Invisible Woman, AKA "WHOREy," is one of the Fantastic Four. She has nice boobs, but we will never see them. She had an affair with The One, becouse she wanted to know if he's the final Cylon, but even he barely knows it.
Tory first appears from nowhere after poor Billy Kayakuya was a killed by a terrorist gone berserk. She organizes a group to cheat on the elections for another nice woman, but one-and-a-half seasons later Tory betrays Roslin, because she wants to live with her people (and frak with atheist priests, maybe).