The details of the Zen'in Clan Incident:

1: Maki returns to the family home to retrieve cursed tools from the Zen'in storehouse for the "Culling Game." Her biological father, Ogi, lies in wait and inflicts fatal wounds on both her and Mai.

2: He throws the dying sisters into a training room filled with a massive number of Cursed Spirits to finish them off.

3: Mai dies, and Maki awakens, leading to Ogi's death.

4: Following Ogi's killing, the Zen'in clan deems Maki to have gone insane and attempts to eliminate her using the "Kukuru Unit" and the "Hei" who were present at the scene.

5: They challenge her in coordination, but they are no match for her, as she has reached the same heights as the former tyrant, and they are annihilated.

6: Naoya, the head of the "Hei" and the last one remaining, is also taken down.

7: Shortly after, 6 members of the Hei, 9 members of the Akari, and 21 members of the Kukuru Unit who were absent from the Zen'in estate at the time also meet tragic deaths.

8: As a result, every member of the Zen'in clan dies, and the family is destroyed.