Gjallarhorn

Background
This sword was created by the King who founded Shiga Kingdom, Ancient King Yamato. At some point in time it was stolen by Zen after he became the No-Life King.

Info
It's a curious sword with drill-shaped edges.

Maze of Trazayuya
Zen stole it, and gave it to Satou, so he could be able to die.

Trivia

 * It's the weakest holy sword in Satou's storage