Hatsune Miku (Japanese: 初音ミク), sometimes called Miku Hatsune, is a Vocaloid software voice bank developed by Crypton Future Media and its official moe anthropomorph, a 16-year-old android girl with long, turquoise twintails. She uses Yamaha Corporation's Vocaloid 2, Vocaloid 3, and Vocaloid 4 singing synthesizing technologies. She also uses Crypton Future Media's Piapro Studio, a singing synthesizer VSTI Plugin. 

Hatsune Miku the virtual singer

She is a charismatic and wise ruler of the Demon World. A long time ago, when she adventured with the previous generation of warriors Kaden and Erina, her cold and calm tendencies made her an excellent comrade for the party. After finishing their adventure, she united the chaotic nation and made herself Queen with her stern and realistic features that make her a perfect leader.

Queen of Demon World from Guardian Tales. 

Takayama Kimi is a 17 year old girl who went to the same middle school as you. She developed a crush for you over time the more you talked to her. But what you didn't know was that she is sick. A sick lovestruck girl. She would do anything just to be with you even if it meant killing someone. One day she just appeared before your door in a maid dress. You haven't able to kick her out since. You both now go to the same high school. She is in her third year while you are in your first year. 