Cessair comes from Diplos, a G-class planet in Tau Ceti, the same star system as Ogros. Around 2000 BC, she stole the Great Seal of Diplos and fled to Earth, where she had a hand in the construction of the Gorsedd of Boscombe Moor in Damnonium, also known as the Nine Travellers. The stone circle defied analysis in future years, as the number of stones present seemed constantly to change - this is probably because Cessair brought at least three Ogri with her and hid them in the stone circle.
As times changed, so did Cessair's identity. Early on, she posed as the Cailleach, also known as the Witch Hag, the Celtic goddess of war, death and magic. According to legend, the raven and crow were the Cailleach's servants and she saw through their eyes. Cessair carried this deception through until the 1970s. She also posed as the Mother Superior of the Convent of the Little Sisters of Saint Gudula, the Wicked Lady Morgana Montcalm who murdered her husband on their wedding night, the recluse Mrs Trefusis, the Brazilian Senhora Camara - and then Miss Vivien Fay of Rose Cottage in Boscawen. In this manner, she was able to keep control of the land on which the stone circle sat.
Cessair's spaceship is capable of travelling through hyperspace, and she kept it parked in hyperspace a few feet above the location of the circle in real space. On board this ship she imprisoned the police officers sent to capture her, and the Megara, justice machines whose purpose was to sentence her following capture. Cessair was able to travel back and forth from the ship, and transport others there as well, through a wand powered by tritium crystals. This wand was also capable of firing deadly blasts and creating a static electrical force field. Her stealing of the Great Seal of Diplos - actually the third segment of the Key to Time, known for its powers of transmutation, transformation and the establishing of hyperspatial and temporal co-ordinates - enabled her to alter both her image and voice, and presumably allowed her to move her ship through hyperspace. She kept the Seal disguised as a crystal necklace which she always wore around her neck.
Cessair has silver skin, is allergic to citric acid and can communicate telepathically with the Ogri, who do not find her Diplosian blood appealing. She was charged with murder and the removal and misuse of the Great Seal of Diplos. The Megara found her guilty of "impersonating a religious personage, to whit, a Celtic goddess - penalty imprisonment for 1500 years; theft of the Great Seal of Diplos - perpetual imprisonment; sentences to run consecutively." Consequentially, Cessair was turned into another stone in the Gorsedd of Boscombe Moor.
