Valerica is the Serana's mother.
After finding out from the Moth Priest that they will another Elder Scroll, Serana wants to find her mother, Valerica, for perhaps she can help them with such task. However, Valerica has been missing for years and Serana looks for clues on where Valerica could be. Fün finds Valerica's notes and Serana snatches the manuscript right from Fün's hands. They go back and forth about this place called Soul Cairn, which is haunted by some pretty powerful beings.
Fün Tits and Serana go to the Soul Cairn, which they dub Houston, to begin searching for Valerica. After a few gallops on her new horse Arvak, Fün finds Valerica, Serana's milf, who has the same part in her hair and comes out quite abruptly, wanting to know the reason why her daughter is in the company of a half-blood. In the middle of all the vampiric nonsense, Valerica says that the key to the Tyranny of the Sun is Serana herself. Which basically means that Japan requires Serana's blood. But... Fün doesn't want Serana to die, so she will try and chose another path. Cold-hearted bitch Valerica interrupts this thought and explains what Fün should do and whom she should kill. (Quest For The Demon Horse Shadowmere)
Fün initiates her mission to go see the Keepers of Soul Cairn, or Houston. Fün quickly destroys the Keepers and goes back to Valerica. Considering the deed quite impressive, Valerica kind of compliments the vampire Pimp, but Fün disregards it, for she has killed as many animals as the number of cells in a body.
Following Valerica and reaching the heart of Houston, Fün slays effortlessly a Poorly Named Dragon. Valerica tells Fün how astonished she is with what happened. Guess she should be around Fün more often, she'd be astonished every day.
At last, Fün obtains the Elder Scroll! Valerica tells Fün and Serana they should get going and that she will stay behind, which Fün appreciates. Not like she wants to have her getting all emotional with her daughter as she tags along. (Failure Dragon)