Mahouka Koukou no Rettousei: Yoru no Tobari ni Yami wa Hirameku The Irregular at Magic High School: The Dark Flashes in the Night's Veil

Synopsis

The story of the spinoff novel follows the Kuroba siblings, who are sworn to protect Tatsuya Shiba. They face a new threat when an enemy from a foreign mafia sets their eyes on Tatsuya. (Source: ANN)