Daughter of Coldharbour
A Daughter of Coldharbour is a female vampire whose vampiric bloodline has special arcane powers, according to dark arcane legend. The mystical qualities of this blood is relevant to a prophecy being pursued by Lord Harkon, which is meant to result in the banishment of the light of the sun, granting freedom to all vampires.
Two known Daughters of Coldharbour are Valerica and Serana, who are mother and daughter, respectively, and who are also the wife and daughter of Lord Harkon. They are actively attempting to deny him the use of their blood to pursue the prophecy. It is worth noting that Lamae Beolfag, the first pureblood vampire, is also a Daughter of Coldharbour.