Praska

 was an Aquillian. She knew that the Seventh Doctor would ruin their plans. She used Rufus Stone as a conduit to carry out those plans. She followed the Doctor's travels throughout all his lives. She protected the north of England from alien invasions. She said that the Hirudines were coming, and that To'Koth was dying. She could telepathically communicate with the Doctor, explaining to him that Hex was a distraction for the Hyrodine. She later told Rufus that To'Koth's death was what was affecting the Earth and that Hirudines wanted his powers. She was impressed by the Doctor's TARDIS. (AUDIO: Signs and Wonders)