My Merry May

This VN tells the story of Kyosuke, a high school student, who lives a normal student's life in a dormitory until one day he receives a strange device from abroad. Inside the device is a female replis, an artificial human being. Kyosuke decides to awaken her, but before her personality is fully loaded, a thunderstorm briefly cuts the energy in the dormitory, creating a bug in Leu's system. Instead of his own personal servant, Kyosuke now has to take care of a teenager with a childlike mind. The remaining cast of heroines include Hitoe Haruna, Yasusuke's childhood friend, Motomi Agatsuma, the girlfriend of Kyosuke's best friend, Ryo Hagimoto, 21-year old Tae Kizuki, and her friend, 13-year old high school student Misao Yuki.

(from RPGfan)