Kyoseiga (巨精牙, Great Spirit Fang) is a sword forged long ago by a powerful shinkitsune from his very own fang. Later, the sword got to Kintaro Tsukihoshi's possession through unknown means. Kintaro gave the sword away to his son Gingichi when he left the Tsukihoshi clan. Neither Kintaro or Gingichi are aware of the swords past as of now.
Obtaining Kyoseiga is one of the goals of Kuyomaro, the twin brother of Kyoseiga's creator.