Haruhi Fujihara is the last son of the Billionare, Tsurgu Fujihara from the prestigious Fujihara family.  Haruhi is a living person with a doll's face, his face can change or expression emotions. He is expressionless like a true doll. 

Haruhi expresses himself in different ways through playing musical instruments or using a sharper marker as a weapon to attack people. 

Haruhi does have a wacky behavior and two overbearing siblings who blame themselves for his lack of emotions; However Haruhi does have his own secrets many of which he shares with Yukiko, Fernando, Tatsuya, Hakuyru, and Satomi.  Sercets that can reveal why his face never changes.