Kara no Kyoukai (空の境界) is a series of novels by Type-Moon's Nasu Kinoko. Kara no Kyoukai takes place in the same universe as the Fate (series), and features the main character named Ryougi Shiki who possesses similar powers to Tohno Shiki.
It was published before Tsukihime, and is considered to be a prototypical version of the game's story. Kara no Kyoukai and Tsukihime are mutually incompatible and take place in different universes.
