Name: Katherine von Swartzchild
Birthday: Some time during the 15th century
Astrological Sign: Unknown
Relationships: Stefan Salvatore, Damon Salvatore
Parents: Baron Von Swartzchild, mother unknown
Powers: Owl form, tiger form, kitten form, weather manipulation, mind manipulation, she can appear in people’s dreams
As the unmarried daughter of a baron, Katherine's full title would have been The Honourable Katerina von Swartzschild
Katherine looks almost exactly like Elena, with jewel-blue eyes, golden blonde hair, and pale skin. There are however a few slight differences between the two girls. Katherine is shorter, her eyes are wider and more blue, and her hair is a few shades darker than Elena's. Katherine also has "almost silvery" eyebrows and eyelashes. She is, of course, very beautiful.
At first, Katherine is described through flashbacks of memory. She finally makes her appearance in The Fury. She looks the same, except for her long, golden hair, which has grown past floor-length and now trails behind her; Elena initially mistakes it for a train on her gown. Her face is also described (by Elena) simply as looking "wrong" and "distorted," twisted by hunger and mocking.
When the Salvatore brothers first meet Katherine during the Renaissance, she is a fragile young German noblewoman with a dark secret. Katherine is soft-spoken, innocent, and excessively naïve. In spite of her vampirism, she does not appear to understand shadow emotions and the darker side of life, and as such she fails to grasp the deep roots of the conflict between Stefan and Damon. She displays her childishness by refusing to choose between the two brothers and believing that martyring herself will resolve their difficulties.
In the centuries between the Italian Renaissance and the time of The Fury, Katherine has grown quite insane, which is at least partly attributable to the influence of Klaus. She is jealous of Elena and hates Damon and Stefan for daring to pursue another woman. She boasts about killing many humans and vampires over the past few centuries, and has become hungry for power and revenge.