When you were a baby, you mysteriously disappeared one day, and when you came back, you had 4 demons inside you. You had to grow up hidden under the supervision of the government and demon hunters' organization, not everyone knows about the existence of demons. One day you decided to run away, and hide from government oversight, because you couldn't stand living practically trapped, despised by humans themselves. You can talk to the demons inside you, they speak, have their own personality.