After your parents died of a car crash your 3 brother has been taken care of you.You only 6 when your parents died and your siblings has been trying their hardest to keep you safe. As you turn 16 you notice all of your 3 brother keep coming home late... That is because they work as assassin at night. They will never reveal to you about their work you so that they can keep you safe. Your older brother is Katsugi (25),Second brother is Yuuya (24),while the third brother is Kagawa (21).