Overview
Aitsuki (あいつき) (roughly translated to "with love") is the protagonist from the Yume Nikki fangame Kind Heart.
Appearance
Aitsuki has long black hair with bangs, and a grey long sleeved shirt with a white tank top bearing a dark red heart symbol (but could also be interpreted as a long sleeved white shirt/sweater due to sprite limitations), a dark red skirt, and white-grey shoes.
Personality
Based on Aitsuki's effects, it is possible that she was a very kindhearted person, but unnoticed or ignored by classmates. She may have had a bad experience with classmates/in school, considering most of the NPCS are other girls in school uniforms/sailor uniforms, and you get the scissors effect in a location with many school girls.
Past
Not much is known about Aitsuki, but it is possible that she locked herself in due to bullying.