Lady Cassandra

Played by Zoë Wanamaker

"Moisturise Me! Moisturise Me!"

First Regular Appearance	Last Regular Appearance
The End of the World	New Earth

Lady Cassandra O'Brien.Δ17 (""dot Delta Seventeen"") viewed herself as the last pure human left in the universe at a time (the year five billion) when the Earth was finally destroyed by the expansion of the Sun. This was a viewpoint challenged by Rose Tyler when she met a woman who had been altered by almost endless cosmetic surgery into what was now a brain in a jar and a face set into skin stretched around a mobile frame. Or, as Rose put it, ""a bitchy trampoline"".

Cassandra thought of nothing but herself, and her constant need for expensive medical procedures was the inspiration behind her deadly plans to exploit Platform One's occupants. When the Ninth Doctor foiled her schemes, he and Rose thought they'd seen the last of her. But the Lady Cassandra had been able to turn the other cheek, and after surviving her fate had hidden away in the depths of a New Earth hospital. It was there she encountered the Tenth Doctor and took possession of Rose's body as she schemed to blackmail the Sisters of Plenitude. When this latest attempt to perpetuate herself failed, Lady Cassandra finally embraced her mortality.