O is for... Ohica

Ohica was a member of the Sisterhood of Karn, who acted as deputy to their High Priestess Maren. Karn lay in the same region of space as Gallifrey, and there were ancient ties between the Sisterhood and the Time Lords. The relationship could be tense, as the despotic Time Lord Morbius had once devastated Karn when he led his followers there, promising them a share of the Elixir of Life. This liquid was produced by a flame which the Sisterhood worshipped. It prolonged their lives and enhanced their mental abilities.

Morbius had been captured here and executed.

The Doctor was able to convince Maren and Ohica that he had not come to the planet to steal their Elixir for the Time Lords (it was used to aid with regeneration difficulties), and that Morbius still lived - his brain secretly retained by a surgeon disciple named Solon, who had completed a hideous new body to house it. The sacred flame was dying and the Elixir running out. 

Ohica led a hunting party which chased the Morbius monster over a cliff, falling to his death.

Maren had been very old when she first took the Elixir, and the Doctor had managed to convince her that without change there could only be stagnation. She sacrificed herself to the flame, and Ohica assumed the leadership of the Sisterhood. The Doctor identified the reason for the dying flame - a blockage in a volcanic vent - and left Ohica with a supply of fireworks to unblock it should this happen again.

Played by: Gilly Brown. Appearances: The Brain of Morbius (1976).