Viktor is Lestat de Lioncourt's biological son introduced in Prince Lestat, and the result of an experiment into vampire physiology performed by Fareed and Seth. His mother is Dr. Flannery Gilman, a (at that time) human woman who participated in the experiment, having sex with Lestat under laboratory conditions. He is described as having an uncanny resemblance to Lestat, having grown his blond hair to a similar length based on videos and photos of his father's time as a rock star, but is notably 6'1", one inch taller than Lestat. He is soft spoken, polite, and slow to anger.
Viktor is raised with full knowledge of the existence of vampires and the identity of his father, and his mother is transformed into a vampire when he is ten years old. He was raised in luxury in a loving household, seeing Fareed and Seth as his adoptive fathers, but due to his secretive origin and family, he did not have contact with other children. He studied at Oxford as a prodigy, where he tried to connect with other mortals.
At nineteen he meets Rose Fisher while she is recovering from being attacked, and the two quickly fall in love and travel together to New York to meet Lestat at Trinity Gate. Viktor insists he be given the Dark Gift, but is told to await Lestat's decision on the issue. Viktor is kidnapped by Rhoshamandes and Benedict, but escapes the bathroom where he is being held by lighting a fire, forcing Benedict to open the door and allowing him to flee.
Finally arriving at Trinity Gate, he meets his biological father, and Lestat grants Viktor permission to recieve the Dark Gift, asking Marius to be his maker due to Marius's aptitude making strong fledglings. Viktor is transformed into a vampire alongside Rose, and the two move to Château de Lioncourt.
In Prince Lestat and the Realms of Atlantis, Victor and Rose assist Lestat with the task of figuring out a way to detatch vampires from the Sacred Core. Later, he is said to be studying medicine with his mother, and speculates on the possibility of humans becoming broadly aware of the existence of vampires. At some point, he and Rose are married at the restored church in the village adjacent to the Château. In Blood Communion, he and Rose hide with Lestat in the crypts, and dance together at the ball at the conclusion of the book.