Yarven

 was one of the Lords on the unnamed planet where the Hydrax landed. He was turned into a vampire, and hid on the Seventh Doctor's TARDIS. When it landed on Earth in Chicago, Yarven fled into the city. (PROSE: Blood Harvest) He was the Vampire Messiah foretold in prophecies known to the Cult of the Vampire Rassilon. Agonal was his father. (PROSE: Goth Opera)