Big Cleanup

Big Cleanup is an incident that occurred in the Middle-East, years before the story.

Description
The events and participants of the Big Cleanup are largely unknown. However, it is known that Edelweiss, the world's strongest swordsman herself, was involved in the events and showcased her abilities there. Sara Bloodlily was also present during the incident and witnessed Edelweiss' swordsmanship, which allowed her to create a copy of her later. Rinna Kazamatsuri showed knowledge of the incident, but it is unknown if the general public is aware of it.

Trivia

 * The incident was called "Big Cleanup" by Rinna Kazamatsuri, who is well known for creating her own nicknames for things. This makes it possible that the actual incident has a different name.