Grim Comet

"A great catalyst is approaching."

- Riku

Every 500 years, the Grim Comet would travel close to Earth. War and famine would spread the land, causing the deaths of many people. Since the human population was declining at the time, the yōkai population was on the rise and this made two powerful Daiyōkai control them in the East and West. One being Tōga, ruler of the West, and the other, Kirinmaru, ruler of the East. The two beast kings joined forces and destroyed a fragment of the comet by Kirinmaru's Blasting Barrage and Tōga's Meidō Zangetsuha.

500 years later, the Grim Comet traveled close to earth once again, and because Tōga is no more, and Kirinmaru has fallen into a long slumber, the sons of the Great Dog Demon joined forces and destroyed the large fragment of the comet with Sesshōmaru's Bakusaiga and Inuyasha's Meidō Zangetsuha.

500 years by the 2021, the Grim Comet appears again. Noticed by Osamu Kirin.