God Slaying Emperor Blade (斬神刀皇) is a sword that belongs to Cocytus.
The blade is an odachi with the length exceeding 180 centimeters.
Among the twenty-one weapons Cocytus has in his possession, it is the sharpest. Its edge is so sharp that it can cleave through magical armor or even physical enhancement. It has very high durability even being used to cut down the lizardmen's hardest armor. In a way, it boasts the highest cutting power out of all Cocytus' weapons.
- Cocytus only unsheathes this weapon to those he has the greatest respect for.
- This weapon looks very different in both the manga and anime. It looks like a normal katana.
- In the English publication of the Light Novel, the God Slaying Emperor Blade name was translated as Imperial Sword Zanshin.