The Daughter of Katerina Petrova was born in 1490. She continued the Petrova bloodline, even though according to the Petrova family book, the line ended with Katherine, because she had a child out of wedlock which was regarded as a great shame.
Elena is a descendant of Katherine and her daughter.
Katherine's daughter has only appeared in Katerina, and was taken away seconds after she was born, leaving Katherine devastated.
She was never shown in the series again.
In a flashback, we see Katherine giving birth back in her human days in Bulgaria. Her mother announces that the child is a girl and hands her over to her husband. Katherine pleads with her father to hold the child just once, but he says that Katherine has disgraced the family enough, and takes the child away.
Katherine's mother tries to calm her daughter, and says that it's better for the child to be given away.
Katherine was then disowned by her family and banished to England. When she returned to her home after turning into a vampire, her entire family was killed by Klaus, but since her daughter was not living with them, she wasn't killed and the Petrova bloodline could continue.
- Katerina (flashback)
- Oleg Petrova, the father of Katherine had said that she had shamed the family enough, meaning that Katherine had the child illegitimately.
- Only Katherine and her parents knew about the child's existence, so when Katherine turned into a vampire, the Originals thought that the Petrova line ended with her, even though it didn't because of her daughter. Elena and Stefan are the only people Katherine told about her daughter's story.
- It is unknown whether Katherine went looking for her daughter after she was turned into a vampire. However, since Katherine was running from the Originals, it can be assumed that she knew it would be dangerous to contact her daughter, as Klaus was unaware of the child's existence.
- Ironically, the child being taken away turned out to be wise, as it kept the Petrova bloodline safe for a few centuries.
- She and Tatia's child have some similarities: