She is Harry's older sister who wants her brother to abandon his obsession with Zoid battles and return home to help their father with their company. After Harry once lost all his Zoids to the Backdraft Group, Mary personally arrived at his estate to demand that he return home, threatening to cut him out of the family fortune if he refused. But when Harry explained about his problems with the Blitz Team, particularly Bit, she agreed to meet with them. Upon meeting the Blitz Team, she quickly disapproved of Leena as Harry's love interest but falls in love with Bit's Liger Zero (it was cute). She then challenged the Blitz Team to a battle with the Liger Zero at stake, offering ten times the normal prize money as an incentive. To assist the Champ Team, Mary purchased Iron Kongs. When the Champ Team lost the battle, Mary changed her opinion regarding Zoid battles and decided to leave Harry be.

(Source: Wikipedia)