Mao is the main character of Disgaea 3.

Mao is the son of the Overlord, who rules the Evil Academy. Mao has never been to school since it began, making him the top Honor Student with a 1.8 million Evil Quotient (E.Q.). But ever since his father stepped on his Slaystation Portable, he vowed to defeat him for what he did. He becomes a hero by stealing Almaz von Almadine Adamant's hero title, and spend a majority of the game going back and forth into his Heart to give the title back.

Other than Mao's fascination (if not sexual pleasure and uncontrollable drooling) with rare specimens to experiment on, Mao is a typical demon: He cares not for other problems unless he benefits and takes what he wants by force.