Alaya

Alaya was a female Silurian warrior from a vast underground city that was disturbed by a Welsh mining facility, in the year 2020. She came to the surface and took people as hostages. She also had a twin sister, Restac, whom she shared a hatred of humans and a desire for war to take the planet 'back' from humaity.

Biography
Alaya and Restac were twin sisters. Restac did not show much concern for Alaya, but she would, when she would die at the hands of Ambrose Northover (DW: Cold Blood).

Alaya came to the surface and took Elliot Northover, Amy Pond, and Mo Northover under ground to be kept as hostages. The Doctor sprayed her with a carbon dioxide fire extinguisher and then Rory bundled her into the back of a Meals on Wheels van.

She was then locked and chained up in the crypt of the church, where she rejected the Doctor's attempts at making peace between the Silurians and humans. When the Doctor and Nasreen Chaudhry left for the Silurian settlement, Alaya said to the remaining group that one of them would kill her and she knew which one, but did not reveal who. (DW: The Hungry Earth)

Death
Alaya had stung Tony Mack when she first returned to the surface, but her venom did not kill him as she thought it would. Ambrose demanded that Alaya provide her a cure for her father, but her refusal provoked her into using a taser on Alaya, unintentionally killing her. With her last words Alaya revealed she had in fact thought that it would be Ambrose who would kill her, as she had the most to lose.

Alaya's death almost sparked a war between humans and Silurians. (DW: Cold Blood)

Personality
Alaya enjoyed hunting humans for sport. She would lie to protect the rest of her species and would kill anyone who tried to provoke her. Alaya was also shown to be rather sadistic, taking pleasure in the fact that Tony Mack was suffering from her venom, though she was surprised that he hadn't succumbed to it. She was also strong willed, refusing to give in when Ambrose tortured her and chose to die rather than tell her how to cure her father. (DW: Cold Blood, The Hungry Earth).