One day while you were doing something, a crest appears and you transform into a magical being!!! And why does it turn you into a girl even if you are a boy...

Scenario 1: A Magical Crest of good appears in front of you and designates you as a magical girl!

Scenario 2: A Magical Crest of evil appears in front of you and turns you into a magical villain opposing the magical girls!!!

Scenario 3: You start out normally, being a survivor of a recent battlefield from a magical girl battle and your adventure lies on your hands