Because of the massacre, a story of rebellion against the imperial court was set off.
The background is self-written, set in an era similar to the Edo period. It does not exist in history.
Because it doesn't exist, the place names are a bit confusing. Apart from Edo, I don't know other place names in old Japan, so the place names will be the names of places in current Japan. [Not used in Tokyo. Tokyo's old name is Edo]