Three light novels created by Matsuri Hino and Ayuna Fujisaki were published in Japan by Hakusensha in 2008 (the first two novels) and 2013 (the third), respectively. The novels feature side-stories that use the characters of the manga, but are not specifically based on chapters from the series.
The first novel, Vampire Knight: Ice Blue’s Sin, was published on April 5, 2008. The first story within the novel looks at an incident that occurred at Cross Academy in the year preceding Yuki’s arrival about a Day Class student named Fuka Kisaragi, while the second story details an incident that occurred while Zero was still in training to be a vampire hunter alongside Kaito Takamiya, another boy training under Toga Yagari to be a vampire hunter.
The second novel, Vampire Knight: Noir’s Trap, was published on October 3, 2008. The story focuses on two minor characters, Nadeshiko Shindo and Kasumi Kageyama, from the manga, following their respective unrequited love at Cross Academy, as well as detailing a case that happened when Akatsuki Kain and Ruka Souen go to visit Senri Shiki and Rima Toya’s modeling studio.
The third novel, Vampire Knight: Fleeting Dreams, was released in 2014, featuring side-stories about Rido Kuran, Sara Shirabuki, and Yuki’s and Zero’s activities during the timeskip. The third novel is the only novel thus far to have been licensed by Viz Media and released in North America.