Kyo Clone-10 is a clone created from the DNA of Kyo Kusanagi. It was revealed in the first game's introduction that he, as well as Iori Clone-09, were created by Gustab Munchausen to assist his efforts in destroying the original Kyo and Iori. When they initially appear, the only thing visible of them are their silhouettes along with the symbols of the Kusanagi and Yagami clans that briefly flash on their backs.
After seemingly being given an upgrade in terms of power before being fully released, both he and Iori Clone-09 are given orders by Gustab to fight the original Kyo and Iori at around the time the first Tournament was about to begin. They were also seemingly assigned to defeat the winner of the Tournament, though they most likely ended up losing to either Kyo, Iori, or Yukino.