About Mai
(Kujaku Mai), also known as Mai Valentine in the Yu-Gi-Oh! series, is a 24 year old duelist who grew up thinking that money was the only thing she ever needed. Her childhood was riddled with getting whatever she wanted with the snap of her fingers, but at the expense of solitude. She didn't have friends, and her family ignored her existence for the most part. With that kind of upbringing, it's no wonder she arrived in the Duelist Kingdom arc with a pompous, self absorbed attitude with her sights solely set on the money as a prize. It was Mai's belief that money was all she needed, because it had always been able to get her what she wanted. That is, until she came across Yugi and his crew of miscreants; seeing what she didn't have made her think things over.
Mai's personality begins to change when she loses a duel to Panik, a Player Killer hired by Maximillion Pegasus to knock duelists out of the tournament. Yugi duels Panik after she loses, manages to win, and returns Mai's star chips. This is a turning point for Mai because she realizes that a friend can be a really helpful thing to have in a time of crisis. One of Mai's most notable quotes in the English dub is, "I used to think the only person on Earth a duelist could trust was herself. Everyone else was just an opponent. Then I met Yugi, and I learned through him that even the strongest opponents in the arena could still be friends outside it."
The blonde also has a very defined sense of honor, despite the perfume method of cheating that she used in duels prior to meeting Yugi and his friends. In exchange for the star chips that Yugi gave Mai, she gave him a tough, honest battle in her final match in Duelist Kingdom. But the best mark of her growth was not that she dueled honestly, but that she knew when to quit. And when Joey/Jounouchi couldn't find his qualification card, Mai gave him hers and some advice, too. I doubt that she'd have done such a thing for anyone if she'd never met Yugi. Overall she transforms into a better person, though still strong and willful as ever.