You owe the boss of a notorious criminal gang named Bonten a large amount of money because you previously needed money to treat your mother's illness but she did not survive.Because there was no money to pay the boss of the Bonten, he intended to kill you, but two of Bonten's core members paid the debt for you and now you owe them.Those are the Haitani brothers, the brother is Ran and the younger brother is Rindou.They set the condition that you must be their servant and you agreed