Ruath

Ruath was a Time Lady, who studied at the Prydon Academy at the same time as the Doctor. She later became the consort of the Vampire Messiah Yarven, and tried to take over Gallifrey with an army of Vampires.

Time at the Prydon Academy
Ruath was in the class of '92 the year above the Doctor. They used to break into capsules together. The Doctor said that Ruath was the first person to lead him astray.

After the Academy
Ruath unlike the Doctor decided to stay on Gallifrey. During this time she became with vampires which started as an academic interest. Ruath was part of a research team studying texts from Rassilon's time. In a volume of the ROO texts, she found a story detailing how Rassilon was bitten by, and became a vampire towards the end of his life. Along with other students of the Undead, she found vampire shrines in the Capitol. Presumably she joined the Cult of the Vampire Rassilon, as she first learnt about the Vampire Messiah from them. Later she used Romana to get to Earth and find Yarven, ironically like the Doctor she also stole a TARDIS.

The Prydonian Lady
"He will be joined by a Prydonian Lady, and the two of them shall cause much suffering." -Prophesy of the Vampire Messiah.

Ruath became the Prydonian Lady prophesised to help Yarven. She rescued him from his grave where he was buried but still alive. When her plan to give him the Doctor's blood failed she gave all her own, which resulted in her second regeneration. Shortly after this Yarven made her a vampire and she became his consort. She then worked on a machine that would plunge planet Earth into a time freeze, creating an everlasting night. When she, and the Doctor met up again as he was trying to foil her plans she expressed anger that he had left, feeling she had been betrayed. (MA: Goth Opera)

The Doctor tricked her into believing he wanted to join her cause and she turned him into a vampire. Ruath then planed to make him her consort once Yarven had sacrificed herself but was caught before this could happen. After Yarven and all the other vampires were destroyed she escaped and confronted the Doctor who revealed to her that he purposefully left her because he believed that she couldn't handle the life of a renegade, which until then was a decision hadn't regretted. When Tegan intervened, Ruath tried to kill her but Nyssa opened the doors of the TARDIS, and Ruath was sucked out into the vortex. The Doctor said that Ruath was most likely dead. (MA: Goth Opera)

Personality
The Doctor said the Ruath he knew from Gallifrey was sincere and, but in Goth Opera Ruath was cruel and showed little for life, shooting Spandrell intending to kill him (although she failed). She was a good leader, brave and confident. When she got excited her voice would rise in pitch. (MA: Goth Opera)

Appearance
Ruath II was tall, straight backed and bound her hair severely. Her features were sharp and inquisitive. She wore a neat black trousersuit and a silver belt with utility packs, along with a necklace of golden spears. Ruath III had black hair that went to her waist, when she regenerated her clothes changed as well to a velvet red gown and gloves. (MA: Goth Opera)