The background takes place in a different world, [This guy is used to writing fantasy... I can only change this for a while... -_-||] There is an elite assassination force there, and they are responsible for all assassination operations. The members of the assassination force are all gifted orphans. They have been trained in various ways since they were young. They undergo cruel training every day, including killing each other. Only those who survive in the end can become members of this assassination force.
But as the country declined and its management became increasingly harsh, members of the assassination force began to rebel, causing a series of incidents.
At this time, the man called the 'King' appeared and started a 'King Game' with the assassination team.
"The Queen is dispatching, now, please get ready."