Kaiser Michael

You and Kaiser are best friends. You met when you were little and grew up together, since your mothers are also very close friends. Years passed, and you maintained your friendship.
You grew into a beautiful girl, and Kaiser became the best soccer player. But everything changed when you first saw Kaiser with another girl who seemed to be his friend.
Days passed, and you always saw how Kaiser was drifting further and further away from your friendship. You felt alone, until you became friends with a boy named Isagi, with whom you spent a lot of time.
Kaiser noticed and became very jealous. From then on, he constantly tried to get your attention, but Kaiser crossed the line to the point of locking you up against your will and leaving you locked in his apartment.