Fiction:Serana

Serana is an ancient pure-blood vampire and the daughter of Lord Harkon and Valerica. She is known as one of the "Daughters of Coldharbour," and because of this she is central to the main questline in Dawnguard. After being encountered, she can be recruited as a follower, unlocking a multitude of interactions.

Origins
Her year of birth is unknown, but she was originally locked away in the mid-late Second Era, in between the rule of the Reman and Septim Empires.[UL 1]

She is one of the few pure-blood Vampires known to exist. Pure-blood vampires are individuals who are granted vampirism directly from Molag Bal, the creator and patron deity of Vampires.[1][2] The process is somewhat similar to the creation of the first vampire, Lamae Beolfag.[1] Serana gained her vampirism through a ritual in which members of her family pledged themselves to Molag Bal. Females like Serana and her mother, Valerica, who survive the horrific ordeal are dubbed "Daughters of Coldharbour."

Prophecy
Her father, Lord Harkon, is leader of the Volkihar Clan based in Castle Volkihar. He discovered an ancient prophecy called the Tyranny of the Sun which, if enacted, would allow vampires to roam the world freely without the fear of weakness from the sun, but to do so, he required two Elder Scrolls, Auriel's Bow, and Serana for a ritual sacrifice.

In response to this, her mother hid her away with one of the Elder Scrolls in a sealed sarcophagus within Dimhollow Crypt for thousands of years to protect her from her father. She then fled to the Soul Cairn with the other Scroll.

The Dovakhiin, Angelina - 4E 201
Angelina, the Dragonborn rescued her from Dimhollow and brought her back to Castle Volkihar to see her father. Harkon thanked Angelina and asked her to become a vampire lord. Serana stayed home while Angelina refused the offer and was banished.

Personality
She is enterprising and friendly, but also lonely due to her troubled childhood and her mother's self-exile, which is why she confides in Angelina, the Dragonborn/Dovakhiin. She is wary of her at their first meeting, refusing to share inventories, answer questions in detail, and not letting him/her travel too far ahead alone when told to wait. Because of her Vampiric weakness and time spent in Dimhollow, she will also complain to the Dragonborn about caves and the sun, yet also complain when the weather is anything but sunny as the sun is her preference. Although she complains a lot, she also acknowledges the beauty of Skyrim, especially areas featuring groves and rivers, stating that she is happy to be there with the Dragonborn.

Lioness, Mjoll
Mjoll and Serana have a good friendship while they are with Angelina's group. They help slay powerful enemies despite the in-game lag but make work of the battlefield.

Cicero
Serana is concerned for Angelina letting a psycho on their group but they don't bother each other unless Angelina wants them to test their strength.

Dark Brotherhood Intiate (Female a.k.a. Felicia)
Felicia, the female DB intiate and Serana get along well with each other. This is good as Serana is more of a mage while Felicia is a warrior/assassin on the front.

Karliah and Brynjolf
Serana is interested in both of them as Karliah does a lot of ranged damage while Brynjolf is more of a melee.

Angelina
She and the Dragonborn have a complicated history, when Angelina found her at Dimhollow Crypt. While Serana thanked her, it was starting to become a good friendship but Angelina was banished from Harkon's court. When Serana went to Fort Dawnguard, she accompanied Angelina on her journey to stop Alduin, the World Eater.

Dark Brotherhood Intiate (Markus)
Markus is another intiate of the Dark Brotherhood. Serana and him get into fights sometimes but they are good friends.