Ku is quite the normal high school girl who feels as if she is drifting through her existence and she always describes herself as being "empty". She never misses a chance to give letters to the mysterious prince in her dreams and frequently talks to him in her thoughts. In reality she is an introverted girl, believing that she lacks good qualities. She appears to be easily overwhelmed by situations that deviate from her previous experiences and expectations.
Source from Wikipeida