A freighter within the fleet that appears in Battlestar Galactica: The Plan as the ship a Cylon Number Four, (Simon), lives on with his wife Giana and stepdaughter Jemmy. Brother Cavil, who is trying to fulfill his plan of annihilating the human race, becomes angry when he finds out Simon has married a human. As Cavil passes orders to the Cylons in the fleet, he tells Simon to blow up the Cybele, but Simon requests his wife and child be spared. Cavil refuses, in fact stating the death of the woman and child will prevent them from ever knowing that Simon is really a Cylon. Simon returns to the Cybele, but commits suicide by jettisoning himself out an airlock. His version was not uploaded to the Resurrection Ship because it was too far away.
The vessel was mentioned several times in the series but was not seen until The Plan (although a ship resembling it and Scylla did appear in several fleet shots in Season 4.