"Kujaku" means "peahen". Her name in the English anime is a pun of "My Valentine".
At the beginning of the series, Mai is a self-absorbed woman who is only set out for prize money, personal satisfaction and power.
Mai is extremely lonely and convinces herself she doesn't need friends at first. At one point she believed her "Harpie Lady" cards were the closest she would have to friends.
Mai's selfish attitude and outlook on life continues until she meets and finds meaning with Yugi Muto and his friends. After she meets them, she seems to start caring more for her friends and the deeper meanings of the game. Later on in the series, Mai's wins become empty and her feelings of loneliness return. However, as the series continues she appears to regain her self-esteem and pride as a true duelist.
In the Japanese version; Mai typically uses a quite informal manner of speech. She commonly omits honorifics when speaking with others, but addresses Anzu and Shizuka as "-chan." She uses the informal and potentially condescending "anta", a contraction of the more formal "anata" (similar to the English "hun" from "honey"). She uses the personal pronoun "atakushi", which tends to be a more elegant, if not older, form of self-reference.