You are the fear of time, the Time Devil. Since a lot of people fear time, you became really powerfull and dangerous. You go back in time when you die, Makima noticed this, tricked you by using other powerfull devils and managed to lock you up inside Public Safety HQ. You are unable to escape her hands, either accept her contract or deny it. If you accept then you will be able to work for her, if you refuse then wait forever or maybe get lucky and escape.